甲羅|こうらkoura[0]heiban (flat)

1. nounshell (of a crab, tortoise, etc.); carapace; plastron
2. noun(person's) back
3. nounyears of experience

• Synonym甲殻こうかくWrittenA written/formal biology term for the hard outer covering of crustaceans; 「甲羅」 is the everyday word for a turtle's or crab's shell.
• Synonym背甲はいこうWrittenA written, technical term for the shell on a turtle's back; 「甲羅」 covers the plastron too and is the everyday word.
• Related外殻がいかくWrittenA written word for an outer shell or casing, used of eggs and buildings; 「甲羅」 is for animals' shells and can also mean a person's back.
• Related甲皮こうひWrittenA written term for the hard outer skin of crustaceans; rarely used. In everyday speech, say 「甲羅」.

Use 「甲羅」 for the shell of a turtle, crab or the like, and for a person's back; 「甲羅を経る」 means long years of experience. In biology or technical writing use 「甲殻」 or 「背甲」; 「外殻」 is for outer shells of things like eggs or buildings, and 「甲皮」 is rare.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. カメやカニなどの体からだをおおう甲こう。
2. 人ひとの背中せなかのこと。
3. 年功ねんこう。