thyrsus UK /ˈθɜːsəs/US /ˈθɜɹsəs/ noun2 •A staff topped with a conical ornament, carried by Bacchus or his followers.In my hand I bear / The thyrsus, tipped with fragrant cones of pine. — 1882 •A species of inflorescence; a dense panicle, as in the lilac and horse-chestnut. formsthyrsi