一いち卵らん性せい双そう生せい児じ

noun

identical twins

Medical and everyday term for twins from a single fertilized egg; contrasts with 二卵性双生児 (fraternal twins).

• 彼かれらは一いち卵らん性せい双そう生せい児じなので、顔かおがそっくりだ。

  They are identical twins, so they look exactly alike.