戊 (wù)

fifth of the ten Heavenly Stems 十天干[shi2 tian1 gan1]; fifth in order;

Etymology

Pictograph of a battle axe. Similar to 戈, 戉, and 戌.

Shuowen Jiezi

《說文》:“戊,中宮也,象六甲五龍相拘絞也。戊承丁,象人脅。”

Original meaning

battle axe