一卵性(いちらんせい)

いちらんせい
noun
identical (twins); monozygotic
formalmedicalfamily
1. identical; monozygotic
Derived from a single fertilized egg, used primarily to describe identical twins who share the same genetic material.
一卵性(いちらんせい)双生児(そうせいじ)。
Identical twins.
二人(ふたり)は一卵性(いちらんせい)の双子(ふたご)だから見分(みわ)けがつかない。
The two are identical twins, so I can't tell them apart.
一卵性(いちらんせい)の双子(ふたご)は遺伝子(いでんし)が同(おな)じだ。
Identical twins have the same genes.

一卵性(いちらんせい) is a scientific term meaning "monozygotic" — derived from a single fertilized egg. It is almost always used as a modifier before 双子(ふたご) or 双生児(そうせいじ).

Etymology

A compound of 一(いち) (one) + 卵(らん) (egg) + 性(せい) (nature/type).

Common expressions

Similar words

  • 一卵性(いちらんせい): identical/monozygotic (from one egg)
  • 二卵性(にらんせい): fraternal/dizygotic (from two eggs)

Usage

双子(ふたご) alone means "twins" without specifying type. 双生児(そうせいじ) is the more formal medical term for twins. In everyday conversation, 一卵性(いちらんせい)の双子(ふたご) is more common than 双生児(そうせいじ).

general
Added 2026.1.29 15:16 · Revised 2026.9.2 13:01
08500/08959_ichiransei