What do the abbreviations in POS tagging etc mean?

Question

Say I have the following Penn Tree:

(S (NP-SBJ the steel strike)
 (VP lasted
     (ADVP-TMP (ADVP much longer)
               (SBAR than
                             


        

Answer 1

Those are the Penn Treebank tags, for example, VP means "Verb Phrase". The full list can be found here