| Chiasma (n.) A commissure; especially, the optic commissure, or crucial union of the optic nerves. Thesaurus Entries adjunct, chiasma, component, contingent, crossing, cruciation, decussation, detachment, detail, division, dole, embodiment, example, exponent, fraction, installment, intercrossing, intersecting, intersection, item, parcel, part, particular, percentage, portion, quadrant, quarter, quota, random sample, remainder, representation, representative, sample, sampling, section, sector, segment, share, specimen, subdivision, subgroup, subspecies, transection, transversion, traversal, type, typification |