n (countable|uncountable|mineral) A semi-pellucid, uncrystallized variety of quartz, presenting various tints in the same specimen, with colors delicately arranged in stripes or bands, or blended in clouds.
n (uncountable|printing) A kind of type, larger than pearl and smaller than nonpareil; in England called ruby.
n (countable|obsolete) A diminutive person; so called in allusion to the small figures cut in agate for rings and seals.
n (countable) A tool used by gold-wire drawers, bookbinders, etc.;—so called from the agate fixed in it for burnishing.
a (obsolete) On the way; agoing; as, to be agate; to set the bells agate.