In the comments on my post about part-of-speech tagging, Manu asks,

Can you post a legend what the pos tags stand for? At the moment I’m working on a project where I use this and I dont know at the moment how much tags there are and what e.g. “JJ”, “IN” and the rest of them means. This would be very helpful.

Ask and you shall receive!

These are the Penn English Treebank POS tags. Here’s the list that I found in an answer at StackOverflow, but you’re on your own for finding out what each of these really means:

  • CC Coordinating conjunction
  • CD Cardinal number
  • DT Determiner
  • EX Existential there
  • FW Foreign word
  • IN Preposition or subordinating conjunction
  • JJ Adjective
  • JJR Adjective, comparative
  • JJS Adjective, superlative
  • LS List item marker
  • MD Modal
  • NN Noun, singular or mass
  • NNS Noun, plural
  • NNP Proper noun, singular
  • NNPS Proper noun, plural
  • PDT Predeterminer
  • POS Possessive ending
  • PRP Personal pronoun
  • PRP$ Possessive pronoun
  • RB Adverb
  • RBR Adverb, comparative
  • RBS Adverb, superlative
  • RP Particle
  • SYM Symbol
  • TO to
  • UH Interjection
  • VB Verb, base form
  • VBD Verb, past tense
  • VBG Verb, gerund or present participle
  • VBN Verb, past participle
  • VBP Verb, non­3rd person singular present
  • VBZ Verb, 3rd person singular present
  • WDT Wh­determiner
  • WP Wh­pronoun
  • WP$ Possessive wh­pronoun
  • WRB Wh­adverb