Chinese names the short-chain carboxylic acids by heavenly-stem ordinals for their carbon count:
甲酸 (C1, formic),
乙酸 (C2, acetic),
丙酸 (C3, propionic),
丁酸 (C4, butyric). The same
甲 'one carbon' is in
甲烷 (methane),
甲醇 (methanol) and
苯甲酸 (benzoic acid).
