An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

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.

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."

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).