(rare, slang, offensive) Either of a pair of siblings born less than 12 months apart, especially if born within the same calendar year or school year or born one year apart.

plural of Irish twin

(relativity) The clock paradox.

(mathematics) Either of a pair of prime numbers that differ by two.

plural of identical twin

One of exactly two siblings produced from the splitting of a single zygote.

Alternative form of twincam

plural of twin quasar

(astronomy) a pair of quasar images formed by gravitational lensing of a single physical quasar

plural of evil twin