An Etymological Dictionary of Astronomy and Astrophysics

1. Generally, a topic or subject of discourse, discussion, meditation, or composition.
   

   2. A unifying or dominant idea, motif, etc., as in a work of art. More specifically, an implicit central concept or message found in a literary work.
      

   3. A recurrent melodic element in a musical composition.
      

   4. Linguistics: The stem of a noun or verb; the part to which inflections are added, especially one composed of the root and an added vowel.

Etymology (EN): M.E. teme, theme, from O.Fr. tesme, from L. thema “a subject, thesis,” from Gk. thema “a proposition, subject, deposit,” literally “something set down,” from PIE root *dhe- “to set, put.”

Etymology (PE): Nedan, literally “(something) set down,” from prefix ne- “down,” → ni- (PIE), + da-, variant of dâ-/dâdan “to give, set” (dah-/dahad “gives”); Mid.Pers. dâdan, dah- “to give, set; create;” O.Pers. dā- “to give;” Av. dā- “to place upon, bestow;” Proto-Ir. *da- “to give” (cf. Skt. dā- “to give, present, offer;” Gk. thema; PIE *dhe- “to set, put,” as above) + word forming suffix -an (as in rowzan, rasan, anjoman, barzan).