甲|こうkou[1]atamadaka (head-high)

1. nouncarapace; shell
2. noun1st in rank; grade A
3. nouninstep; back of hand
4. noun, lawthe A party (e.g. in a contract); the first party; plaintiff (label in legal documents)
   甲こうの損そんは乙おつの得とく。↗

   One man's gain is another man's loss.

• Synonym甲羅こうらNeutralThe shell of a turtle or crab; figuratively also a person's back or years of experience, as in 「甲羅を経る」. 「甲」 is a single character seen mostly in compounds.
• Synonym甲殻こうかくWrittenWritten/formal prose; in biology, the outer shell of crustaceans, as in 「甲殻類」. 「甲」 is broader in scope.
• Synonym背甲はいこうWrittenWritten/formal prose; the shell on the back of a turtle or the like. 「甲」 is the general term.
• Synonym甲皮こうひWrittenWritten/formal prose; the hard skin covering an animal's body surface. 「甲」 is the more concise word.
• Antonym乙おつWrittenWritten/formal prose; the second of the ten stems or grade B, the counterpart of 「甲」 in order and rank.

Use 「甲」 for the first of the ten stems, grade A, or Party A in a contract, as in 「甲乙つけがたい」. For a turtle's or crab's shell use 「甲羅」; for the biological shell of crustaceans, 「甲殻」. Its opposite is 「乙」.

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

1. きのえ。十干じっかんの1番目ばんめ。
2. （コウ）甲羅こうら、甲殻こうかく。
3. （コウ）手足てあしの表ひょう。
4. （コウ）複数ふくすうの物事ものごとの内うち、最初さいしょに取り上とりあげるものを呼よぶ語ご。