sial

[sahy-al] /ˈsaɪ æl/
noun, Geology
1.
the assemblage of rocks, rich in silica and alumina, that comprise the continental portions of the upper layer of the earth's crust.
Compare sima1 .
Origin
1920-25; < German, equivalent to Si(licium) silicium + Al(uminium) aluminum
Related forms
sialic, adjective
British Dictionary definitions for sial

sial

/ˈsaɪəl/
noun
1.
the silicon-rich and aluminium-rich rocks of the earth's continental upper crust, the most abundant individual rock being granite
Derived Forms
sialic (saɪˈælɪk) adjective
Word Origin
C20: si(licon) + al(uminium)