Suffixes

-cide

-cycle

-cracy

-ic

-ism

-ist

-ography

-oid

-ology

-omics

-onomy

-onym

-philia

-phobia

-scope

-stan

-ware

-oid is a suffix much used in the sciences and mathematics to indicate a "similarity, not necessarily exact, to something else". According to the Oxford English Dictionary, -oid is derived from the Latin suffix -oides taken from Greek and meaning "having the likeness of".

Thus, asteroid means "like a star" and rhomboid means "like a lozenge, or rhombus". There are many examples of such words: anthropoid , alkaloid, factoid, trapezoid, and so forth.

When nouns formed using -oid are turned into adjectives, the suffix usually becomes -oidal.