You know the word 彼氏 (kareshi), boyfriend. But have you ever wondered what that second kanji actually means?
氏 (shi/uji) is one of the oldest identity markers in Japanese. It means "clan", "lineage", or simply "Mr. /Ms. " , and it is everywhere. When you fill out a form in Japan, 氏名 (shimei) asks for your name. When a news anchor refers to someone formally, they say X氏 (X-shi). And when Murasaki Shikibu wrote the world's first novel, she named her shining prince 光源氏 (Hikaru Genji): "shining one of the Minamoto clan. "
The kanji shows a person bending forward, pointing to the ground, to the low, the foundational, the root of a family. That connects 氏 to 底 (soko, bottom) and 低 (hikui, low): the foundation your family is built on. So 彼氏 (kareshi)? It combines 彼 (kare, "that/he") with 氏 (shi) as a formal way to refer to a person: "that gentleman. " In old Japan, knowing someone's 氏 (uji) told you everything: their rank, their ancestors, their place in society. Now 彼氏 (kareshi) just means your boyfriend.