thematic

adjective

1. of or relating to a theme.
2. Grammar.
   1. (of a word or words) of, relating to, or producing a theme or themes.
   2. (of a vowel) pertaining to the theme or stem: the thematic vowel ends the stem and precedes the inflectional ending of a word form, as i in Latin audiō “I hear.”

adjective

1. of, relating to, or consisting of a theme or themes
2. linguistics denoting a word that is the theme of a sentence
3. grammar
   1. denoting a vowel or other sound or sequence of sounds that occurs between the root of a word and any inflectional or derivational suffixes
   2. of or relating to the stem or root of a word

noun

4. grammar a thematic vowel“-o-” is a thematic in the combining form “psycho-”

adj.1690s, from Greek thematikos, from thema (see theme). Related: Thematically.