thyrse noun2 •A type of inflorescence; a compact panicle having an obscured main axis and cymose subaxes.The example of the thyrse of Eugenia leads us to understand several inflorescences which resemble also racemes or panicles; such are the thyrses of the Lilac. — 1840 •(no longer used) A thyrsus (staff with conical ornament). formsthyrses