双生児

1. Origins, structure, and basic meaning

• Structure: 双生児 is read as そうせいじ and is a noun for twins, two children born from the same pregnancy.
• Basic usage: Twins with opposite personalities appear in 性格が正反対の双生児, while recording each twin’s growth appears in 双生児の成長をそれぞれ記録する.

2. Common pitfalls and similar expressions

• The pair and each individual
  • The word denotes twins as a pair, but それぞれ allows the two individuals to be considered separately.
• Difference from 双子
  • The meanings are close, but this term is relatively formal and readily appears in medical or documentary contexts rather than ordinary conversation.