from
The Collaborative International Dictionary of English v.0.48
Jet \Jet\, n. [OF. jet, jayet, F. ja["i]et, jais, L. gagates,
fr. Gr. ?; -- so called from ? or ?, a town and river in
Lycia.] [written also {jeat}, {jayet}.] (Min.)
A variety of lignite, of a very compact texture and velvet
black color, susceptible of a good polish, and often wrought
into mourning jewelry, toys, buttons, etc. Formerly called
also {black amber}.
[1913 Webster]
{Jet ant} (Zool.), a blackish European ant ({Formica
fuliginosa}), which builds its nest of a paperlike
material in the trunks of trees.
[1913 Webster]