What does agate mean?
The definition of agate
A*gate”, adv.
Etym: [Pref. a- on + gate way.]

On the way; agoing; as, to be agate; to set the bells agate. [Obs.] Cotgrave.

Ag”ate, n.
Etym: [F. agate, It. agata, L. achates, fr. Gr.

1 (Min.)
A semipellucid, uncrystallized variety of quartz, presenting various tints in the same specimen. Its colors are delicately arranged in stripes or bands, or blended in clouds.

Note: The fortification agate, or Scotch pebble, the moss agate, the clouded agate, etc., are familiar varieties.

2 (Print.)
A kind of type, larger than pearl and smaller than nonpareil; in England called ruby.

Note: This line is printed in the type called agate.

3 A diminutive person; so called in allusion to the small figures cut in agate for rings and seals. [Obs.] Shak.
4 A tool used by gold-wire drawers, bookbinders, etc.; — so called from the agate fixed in it for burnishing.