Share this entry

Share this page


Line breaks: sial
Pronunciation: /ˈsʌɪəl

Definition of sial in English:


[mass noun] Geology , dated
The material of the upper or continental part of the earth’s crust, characterized as relatively light and rich in silica and alumina. Contrasted with sima.
Example sentences
  • The rocks found in the crust of the continents is called sial.
  • A mnemonic term derived from for silica, for alumina, and for magnesium, applied as a compositional term to a layer within the Earth that occupies a position intermediate between sial and sima.


1920s: from the initial letters of silica and alumina.

Definition of sial in:

Share this entry

Share this page


What do you find interesting about this word or phrase?

Comments that don't adhere to our Community Guidelines may be moderated or removed.

Get more from Oxford Dictionaries

Subscribe to remove adverts and access premium resources

Word of the day apathetic
Pronunciation: apəˈθɛtɪk
showing or feeling no interest, enthusiasm, or concern