di-tri-a compendious way of expressing di- or tri-, di- and tri-, in composition, as di-trichotomous= dichotomous or trichotomous, di-trimerous (abbreviated 2–3 -merous, cf. 2–3 -fid, 2–3 -celled, etc.).1838Loudon Encycl. Plants (1841) 57 Trichodium caninum, Branches of panicle di-trichotomous roughish, glumes acute.1847Craig, Ditrichotomous, divided into twos or threes; having the stems continually dividing into double or treble ramifications; the term is sometimes applied to a panicle of flowers.[So in later Dicts.]