On the oracle bones, 甲 was often just a cross — the crisscrossing seams of a warrior's armor plates, or the pattern of cracks that spread across a heated divination shell. Later scribes drew a diamond around the cross to make the shell shape unmistakable. Because a fresh shell or plate was always readied and numbered first, 甲 also became China's word for "first" — the very "A" of its oldest ranking system.
A piece of culture
The shell in "oracle bones" The very oracle bones this course keeps returning to have a name built from this character: 甲骨文 (jiǎgǔwén), "shell-and-bone script" — 甲 for the turtle shells, 骨 for the ox bones the Shang diviners carved. 甲 is also the first of the ten Heavenly Stems (天干), an ancient counting cycle still in daily use: Chinese contracts still label their two sides 甲方 and 乙方 — "Party A" and "Party B" — echoing the old ranking 甲, 乙, 丙, 丁 (first, second, third, fourth). The traditional 60-year calendar cycle begins each round with 甲子, literally "stem one, branch one."
Use it in a real word
甲虫
jiǎchóng · gaap3 cung4
beetle — literally "armored insect"; you already know 虫