What is pos of `r` or `s` in Wordnet via NLTK

Question

I am accessing Wordnet via nltk. If I look up the word big, I find some unknown parts of speech like s or r. The docs say "a synset is identified with a 3-part name of the form: word.pos.nn." The WordNet does not seem to mention a part of speech that could be shortened to s or r. So what are these synsets?

$wordnet.synsets('big')
[Synset('large.a.01'), Synset('big.s.02'), Synset('bad.s.02'), Synset('big.s.04'), Synset('big.s.05'), Synset('big.s.06'), Synset('boastful.s.01'), Synset('big.s.08'), Synset('adult.s.01'), Synset('big.s.10'), Synset('big.s.11'), Synset('big.s.12'), Synset('big.s.13'), Synset('big.r.01'), Synset('boastfully.r.01'), Synset('big.r.03'), Synset('big.r.04')]

Answer 1

 s  =  adjective satellite
 r  =  adverb

See http://wordnet.princeton.edu/man/wndb.5WN.html