theca Thebesian • thecae · · · Info · Definitions · Synonyms · Characters · · theca · · Text Latin · · Script 5 · · Length Definitions · · · (noun) a case or sheath especially a pollen sac or moss capsule. Synonyms: sac. · · Noun Definition 1 (noun) outer sheath of the pupa of certain insects. · · Noun Definition 2 Synonyms · · · sac · · Synonym 1 Characters · · a latin small letter a U+0061 c latin small letter c U+0063 e latin small letter e U+0065 h latin small letter h U+0068 t latin small letter t U+0074