a blue pigment consisting of sodium and aluminium silicates and some sodium sulphide, obtained by powdering natural lapis lazuli or made synthetically: used in paints, printing ink, plastics, etc
2.
a vivid blue colour
—adj
3.
of the colour ultramarine
4.
from across the seas
[C17: from Medieval Latin ultramarinus, from ultrā beyond (see ultra-) + mare sea; so called because the lapis lazuli from which the pigment was made was imported from Asia]
1598, "blue pigment made from lapis lazuli," from M.L. ultramarinus, lit. "beyond the sea," from ultra- "beyond" + marinus "of the sea." So called because the mineral was imported from Asia by sea.