(adj) having a usually flat-topped flower cluster in which the main and branch stems each end in a flower that opens before those below it or to its side
The Collaborative International Dictionary of English (GCIDE) v.0.53 Collaborative International Dictionary (GCIDE)
{ } a. [ L. cymosus full of shoots: cf. FF. cymeux. See Cyme. ] (Bot.) Having the nature of a cyme, or derived from a cyme; bearing, or pertaining to, a cyme or cymes. [ 1913 Webster ]