Armour and helmet together are written 甲胄 in classical Chinese.
Tips
history
胄 is not used alone in modern Chinese. It is bound in 甲胄 (armour and helmet) and 华胄 (noble descendants). Two originally separate characters, "helmet" and "lineage", merged into this one shape: a 由 head element over a flesh ⺼ base.
mistakes
Do not confuse 胄 (helmet / descendants, 由 on top) with the look-alike 胃 (stomach, 田 on top), the top boxes differ by one stroke that pokes through.
⺼ is the flesh-body radical, the form of 肉 used in body words. In the lineage sense it stands for offspring of one's own flesh and blood; in the unified character it serves as the base under the head element.
