AN'NULAR, adjective [Latin annulus, a ring, from Celtic ain, a circle, and ul, young, small; annulus, a little circle.] Having the form of a ring; pertaining to a ring. Annular crystal is when a hexahedral prism has six, or an octahedral prism eight marginal faces, disposed in a ring about each base; or when these prisms are truncated on all their terminal edges.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI