milk · breast

1. Origins, structure, and basic meaning

• Structure: 乳 has meanings related to milk or the breast and is read にゅう in 牛乳 and 母乳.
• Basic usage: 牛乳, read ぎゅうにゅう, means cow's milk; 母乳, read ぼにゅう, means breast milk.

2. Common pitfalls and similar expressions

• The source of milk
  • 牛乳 and 母乳 both concern milk, but from different sources.
  • The broad English word milk does not make the two Japanese words interchangeable.
• A word referring to a person
  • 乳児, read にゅうじ, means an infant.
  • 乳児用の椅子 means a chair for infants: 乳児 refers to a child, not a liquid or a body part.