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index.noun, data.noun, index.verb, data.verb, index.adj, data.adj, index.adv, data.adv - WordNet database files

noun.exc, verb.exc. adj.exc adv.exc - morphology exception lists

sentidx.vrb, sents.vrb - files used by search code to display sentences illustrating the use of some specific verbs


For each syntactic category, two files are needed to represent the contents of the WordNet database - index. pos and data. pos , where pos is noun , verb , adj and adv . The other auxiliary files are used by the WordNet library's searching functions and are needed to run the various WordNet browsers.

Each index file is an alphabetized list of all the words found in WordNet in the corresponding part of speech. On each line, following the word, is a list of byte offsets (synset_offset s) in the corresponding data file, one for each synset containing the word. Words in the index file are in lower case only, regardless of how they were entered in the lexicographer files. This folds various orthographic representations of the word into one line enabling database searches to be case insensitive. See wninput(5WN) for a detailed description of the lexicographer files

A data file for a syntactic category contains information corresponding to the synsets that were specified in the lexicographer files, with relational pointers resolved to synset_offset s. Each line corresponds to a synset. Pointers are followed and hierarchies traversed by moving from one synset to another via the synset_offset s.

The exception list files, pos .exc , are used to help the morphological processor find base forms from irregular inflections.

The files sentidx.vrb and sents.vrb contain sentences illustrating the use of specific senses of some verbs. These files are used by the searching software in response to a request for verb sentence frames. Generic sentence frames are displayed when an illustrative sentence is not present.

The various database files are in ASCII formats that are easily read by both humans and machines. All fields, unless otherwise noted, are separated by one space character, and all lines are terminated by a newline character. Fields enclosed in italicized square brackets may not be present.

See wngloss(7WN) for a glossary of WordNet terminology and a discussion of the database's content and logical organization.

Index File Format

Each index file begins with several lines containing a copyright notice, version number and license agreement. These lines all begin with two spaces and the line number so they do not interfere with the binary search algorithm that is used to look up entries in the index files. All other lines are in the following format. In the field descriptions, number always refers to a decimal integer unless otherwise defined.

lemma  pos  synset_cnt  p_cnt  [ptr_symbol...]  sense_cnt  tagsense_cnt   synset_offset  [synset_offset...]

lower case ASCII text of word or collocation. Collocations are formed by joining individual words with an underscore (_ ) character.
Syntactic category: n for noun files, v for verb files, a for adjective files, r for adverb files.

All remaining fields are with respect to senses of lemma in pos .

Number of synsets that lemma is in. This is the number of senses of the word in WordNet. See Sense Numbers below for a discussion of how sense numbers are assigned and the order of synset_offset s in the index files.
Number of different pointers that lemma has in all synsets containing it.
A space separated list of p_cnt different types of pointers that lemma has in all synsets containing it. See wninput(5WN) for a list of pointer_symbol s. If all senses of lemma have no pointers, this field is omitted and p_cnt is 0 .
Same as sense_cnt above. This is redundant, but the field was preserved for compatibility reasons.
Number of senses of lemma that are ranked according to their frequency of occurrence in semantic concordance texts.
Byte offset in data.pos file of a synset containing lemma . Each synset_offset in the list corresponds to a different sense of lemma in WordNet. synset_offset is an 8 digit, zero-filled decimal integer that can be used with fseek(3) to read a synset from the data file. When passed to read_synset(3WN) along with the syntactic category, a data structure containing the parsed synset is returned.

Data File Format

Each data file begins with several lines containing a copyright notice, version number and license agreement. These lines all begin with two spaces and the line number. All other lines are in the following format. Integer fields are of fixed length, and are zero-filled.

synset_offset  lex_filenum  ss_type  w_cnt  word  lex_id  [word  lex_id...]  p_cnt  [ptr...]  [frames...]  |   gloss

Current byte offset in the file represented as an 8 digit decimal integer.
Two digit decimal integer corresponding to the lexicographer file name containing the synset. See lexnames(5WN) for the list of filenames and their corresponding numbers.
One character code indicating the synset type:

n    NOUN
v    VERB
Two digit hexadecimal integer indicating the number of words in the synset.
ASCII form of a word as entered in the synset by the lexicographer, with spaces replaced by underscore characters (_ ). The text of the word is case sensitive, in contrast to its form in the corresponding index. pos file, that contains only lower-case forms. In data.adj , a word is followed by a syntactic marker if one was specified in the lexicographer file. A syntactic marker is appended, in parentheses, onto word without any intervening spaces. See wninput(5WN) for a list of the syntactic markers for adjectives.
One digit hexadecimal integer that, when appended onto lemma , uniquely identifies a sense within a lexicographer file. lex_id numbers usually start with 0 , and are incremented as additional senses of the word are added to the same file, although there is no requirement that the numbers be consecutive or begin with 0 . Note that a value of 0 is the default, and therefore is not present in lexicographer files.
Three digit decimal integer indicating the number of pointers from this synset to other synsets. If p_cnt is 000 the synset has no pointers.
A pointer from this synset to another. ptr is of the form:

pointer_symbol  synset_offset  pos  source/target

where synset_offset is the byte offset of the target synset in the data file corresponding to pos .

The source/target field distinguishes lexical and semantic pointers. It is a four byte field, containing two two-digit hexadecimal integers. The first two digits indicates the word number in the current (source) synset, the last two digits indicate the word number in the target synset. A value of 0000 means that pointer_symbol represents a semantic relation between the current (source) synset and the target synset indicated by synset_offset .

A lexical relation between two words in different synsets is represented by non-zero values in the source and target word numbers. The first and last two bytes of this field indicate the word numbers in the source and target synsets, respectively, between which the relation holds. Word numbers are assigned to the word fields in a synset, from left to right, beginning with 1 .

See wninput(5WN) for a list of pointer_symbol s, and semantic and lexical pointer classifications.

In data.verb only, a list of numbers corresponding to the generic verb sentence frames for word s in the synset. frames is of the form:

f_cnt   +   f_num  w_num  [ +   f_num  w_num...]

where f_cnt a two digit decimal integer indicating the number of generic frames listed, f_num is a two digit decimal integer frame number, and w_num is a two digit hexadecimal integer indicating the word in the synset that the frame applies to. As with pointers, if this number is 00 , f_num applies to all word s in the synset. If non-zero, it is applicable only to the word indicated. Word numbers are assigned as described for pointers. Each f_num  w_num pair is preceded by a + . See wninput(5WN) for the text of the generic sentence frames.

Each synset contains a gloss. A gloss is represented as a vertical bar (| ), followed by a text string that continues until the end of the line. The gloss may contain a definition, one or more example sentences, or both.

Sense Numbers

Senses in WordNet are generally ordered from most to least frequently used, with the most common sense numbered 1 . Frequency of use is determined by the number of times a sense is tagged in the various semantic concordance texts. Senses that are not semantically tagged follow the ordered senses. The tagsense_cnt field for each entry in the index.pos files indicates how many of the senses in the list have been tagged.

The cntlist(5WN) file provided with the database lists the number of times each sense is tagged in the semantic concordances. The data from cntlist is used by grind(1WN) to order the senses of each word. When the index .pos files are generated, the synset_offset s are output in sense number order, with sense 1 first in the list. Senses with the same number of semantic tags are assigned unique but consecutive sense numbers. The WordNet OVERVIEW search displays all senses of the specified word, in all syntactic categories, and indicates which of the senses are represented in the semantically tagged texts.

Exception List File Format

Exception lists are alphabetized lists of inflected forms of words and their base forms. The first field of each line is an inflected form, followed by a space separated list of one or more base forms of the word. There is one exception list file for each syntactic category.

Note that the noun and verb exception lists were automatically generated from a machine-readable dictionary, and contain many words that are not in WordNet. Also, for many of the inflected forms, base forms could be easily derived using the standard rules of detachment programmed into Morphy (See morph(7WN) ). These anomalies are allowed to remain in the exception list files, as they do no harm.

Verb Example Sentences

For some verb senses, example sentences illustrating the use of the verb sense can be displayed. Each line of the file sentidx.vrb contains a sense_key followed by a space and a comma separated list of example sentence template numbers, in decimal. The file sents.vrb lists all of the example sentence templates. Each line begins with the template number followed by a space. The rest of the line is the text of a template example sentence, with %s used as a placeholder in the text for the verb. Both files are sorted alphabetically so that the sense_key and template sentence number can be used as indices, via binsrch(3WN) , into the appropriate file.

When a request for FRAMES is made, the WordNet search code looks for the sense in sentidx.vrb . If found, the sentence template(s) listed is retrieved from sents.vrb , and the %s is replaced with the verb. If the sense is not found, the applicable generic sentence frame(s) listed in frames is displayed.


Information in the data.pos and index.pos files represents all of the word senses and synsets in the WordNet database. The word , lex_id , and lex_filenum fields together uniquely identify each word sense in WordNet. These can be encoded in a sense_key as described in senseidx(5WN) . Each synset in the database can be uniquely identified by combining the synset_offset for the synset with a code for the syntactic category (since it is possible for synsets in different data.pos files to have the same synset_offset ).

The WordNet system provide both command line and window-based browser interfaces to the database. Both interfaces utilize a common library of search and morphology code. The source code for the library and interfaces is included in the WordNet package. See wnintro(3WN) for an overview of the WordNet source code.


Base directory for WordNet. Default is /usr/local/WordNet-3.0 .
Directory in which the WordNet database has been installed. Default is WNHOME/dict .


Base directory for WordNet. Default is C:\Program Files\WordNet\3.0 .


database index files
database data files
files of sentences illustrating the use of verbs
pos .exc
morphology exception lists


grind(1WN) , wn(1WN) , wnb(1WN) , wnintro(3WN) , binsrch(3WN) , wnintro(5WN) , cntlist(5WN) , lexnames(5WN) , senseidx(5WN) , wninput(5WN) , morphy(7WN) , wngloss(7WN) , wngroups(7WN) , wnstats(7WN) .

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