- Having four sides (as a tetragon); quadrilateral.
- (crystallography) Having two equal axes and one unequal, and all angles 90Â°.
<!--this belongs on the page for "truncate"
- (past of, truncate)
verb (twin, n, ing)
- Either of two people (or, less commonly, animals) who shared the same uterus at the same time; one who was born at the same birth as a sibling.
- Either of two similar or closely related objects, entities etc.
- (italbrac, transitive, obsolete except Scotland) To separate, divide.
- (italbrac, intransitive, obsolete except Scotland) To split, part; to go away, depart.
- (usually in the passive) To join, unite; to form links between (now especially of two places in different countries).
- Placetown in England is twinned with Machinville in France.
- (intransitive) To give birth to twins.
- Forming a pair of twins.
- the twin boys
- Forming a matched pair.
- twin socks
- action of the verb to twin
- giving birth to twins
- the pairing of similar objects (such as towns)
- (context, mineralogy) the formation of twin crystals
- (context, transportation) the conversion of a road into a dual carriageway