Theme vowel

Definition
Theme vowel is a morphological marker which indicates which is the declensional or conjugational class that a word belongs to.

Example
In Ancient Greek, nouns are grouped into three declensional classes. If a noun belongs to the first declension, the root is followed by the theme vowel -a-, and if it belongs to the second declension the root is followed by -o-: mÃ´us+a+n (acc.sg.), mÃ´us+a+y (nom.pl.) 'Muse', log+o+n (acc.sg.), log+o+y (nom.pl.) 'word'. Another term is 'extension vowel'.

Links

 * Utrecht Lexicon of Linguistics