子(こ)

子(こ) is a fundamental word meaning child. It functions both as a standalone word and as a productive element in many compounds.

Common expressions

• いい子(こ): good child (also used to praise pets)
• 男(おとこ)の子(こ): boy
• 女(おんな)の子(こ): girl
• あの子(こ): that child/kid (casual; also used for young adults)

AS A PREFIX (= young/baby):

• 子犬(こいぬ): puppy
• 子猫(こねこ): kitten
• 子鹿(こじか): fawn
• 子牛(こうし): calf

In compounds

• 親子(おやこ): parent and child
• 子供(こども): children (most common form)
• 子育(こそだ)て: child-rearing

Usage

あの子(こ) can refer to young adults casually, not just children. In this usage, it is similar to "that person" but informal.