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.
Other meanings
Either of two similar or closely related objects, plans, institutions, people, etc.
“Your idea is the twin of mine.”
Either of two or more things, people, etc. that share a single feature.
Word history
From Old English "ġetwin".
Where this comes from
This definition is adapted from “twin” on Wiktionary, by its contributors, published under CC BY-SA 4.0. This page is published under the same licence.