twin

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.

A room in a hotel, guesthouse, etc. with two beds; a twin room.

A two-engine aircraft.

A twin crystal.

To separate, divide.

To split, part; to go away, depart.

To join, unite; to form links between (now especially of two places in different countries); to pair with.

Reading, the English town, is twinned with Clonmel in Ireland.

Coventry twinned with Dresden as an act of peace and reconciliation, both cities having been heavily bombed during the war.

To give birth to twins.

“I’ve run to tell ye,” said the junior shepherd, supporting his exhausted youthful frame against the doorpost, “that you must come directly. Two more ewes have twinned — that’s what’s the matter, Shepherd Oak.”

Twinning today is abnormal in all higher primates, and possibly adaptive only in the one species with an obstetrical technology that permits a high rate of survival of twins.

To be, or be like, a twin to (someone else); to match in some way.

The invert child and her innocent child are together lost children, twinning each other despite their distinctions.

I was awake to the horror of our twinning each other in paralysis, and feared that we would soon talk only about the daily, intimate care serious paralysis demands […]

Double; dual; occurring as a matching pair.

twin beds, twin socks

Forming a pair of twins.

the twin boys