jiǎ

1st heavenly stem, fingernail

Origin unclear. Possibly depicts cracks on a shell or tree bark.

Evolution

甲 Oracle script (~1250-1000 BC)

Oracle script

(~1250-1000 BC)
甲 Bronze script Early Western Zhou (~1000 BC)

Bronze script

Early Western Zhou (~1000 BC)
甲 Seal script Shuowen (~100 AD)

Seal script

Shuowen (~100 AD)
甲 Clerical script Eastern Han dynasty (25-220 AD)

Clerical script

Eastern Han dynasty (25-220 AD)
甲 Regular script Modern

Regular script

Modern
Definitions

 

jiǎ

armor, shell; fingernails; 1st heavenly stem; first of the ten Heavenly Stems 十天干[shí​tiān​gān]; (used for an unspecified person or thing); first (in a list, as a party to a contract etc); letter "A" or roman "I" in list "A, B, C", or "I, II, III" etc; armor plating; shell or carapace; (of the fingers or toes) nail; bladed leather or metal armor (old); ranking system used in the Imperial examinations (old); civil administration unit in the baojia 保甲[bǎo​jiǎ] system (old); ancient Chinese compass point: 75°

Most common words with 甲
Freq.
Word
Meaning

armor plating

指甲

fingernail

甲板

deck (of a boat etc)

装甲

vehicle armor

甲状腺

thyroid gland

Component uses

Meaning component in 1 character (0 verified)

Sound component in 13 characters (2 verified)

Sources

季旭昇《說文新證》p.957-958

李学勤《字源》p.1270-1271