One twin, the 'donor' twin, is small and anemic, the other, the 'recipient' twin, is large and polycythemic. The lives of both twins are endangered by this condition.

TWIN definition: either of two children or animals brought forth at a birth. See examples of twin used in a sentence.

There are different types of twins, identical and fraternal being the most common. Identical, or monozygotic, twins develop from the same fertilized egg that splits into two. These twins are...

Jan 2, 2026 · twin, either of two young who are simultaneously born from one mother. Twinning, common in many animals, is of two biological kinds: the one-egg (monozygotic), or identical, …

Dec 13, 2025 · Identical twins, also known as monozygotic twins, share the same egg at conception and are always either both boys or both girls. Fraternal twins, also known as …

TWIN meaning: 1. either of two children born to the same mother on the same occasion: 2. one of two very similar…. Learn more.

1. Being two or one of two offspring born at the same birth: twin sisters. 2. Being two or one of two identical or similar people, animals, or things: twin cities; a twin bed. 3. Botany Of or relating to …