See Also: chalkboard(dictionary)

sial (iou) and chalkboard (oh)


sial (iou)



sial noun. E20.
[from SI(LICON + AL(UMINIUM.]
Geology. The layer of the earth's crust represented by the continental masses, composed of rocks rich in silica and alumina; the material of which this is composed. Cf. SIMA.

chalkboard (oh)



AmE a blackboard
::She wrote the day's menu up on a chalkboard.