Q. How are the senses in WordNet ordered?
A. WordNet senses are ordered using sparse data from semantically tagged text. The order of the senses is given simply so that some of the most common uses are listed above others (and those for which there is no data are randomly ordered). The sense numbers and ordering of senses in WordNet should be considered random for research purposes.
Q. What are the frequency counts?
A. Frequency counts are based on the number of senses a word has.
Q. How can I calculate the semantic distance between two word senses?
A. One method is to use Ted Pederson's open source Perl module, WordNet::Similarity. It provides a number of measures of semantic similarity and semantic relatedness based on WordNet. Given two synsets, it will return a numeric score showing their degree of similarity/relatedness according to various measures that all rely on WordNet in different ways.