-oid
| Suffixes |
| -cide |
| -cycle |
| -cracy |
| -dom |
| -ic |
| -ism |
| -ist |
| -mania |
| -ography |
| -oid |
| -ology |
| -omics |
| -onomy |
| -onym |
| -philia |
| -phobia |
| -scope |
| -stan |
| -ville |
| -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.