俗 means “worldly, common, vulgar”

ぞく · zoku

Also: customs, manners, worldliness

On'yomi (Chinese reading)
ゾク

JLPT N1 · Taught in secondary school · 9 strokes

The story

A person (亻) down in the valley (谷): picture ordinary folk living far below the mountain temples. 俗 is the common world: 俗に言う is "as people say", 俗語 is slang, 民俗 folk custom, and 俗っぽい is cheap and vulgar.

Used in 俗に (zoku ni, commonly/popularly), 民俗 (minzoku, folk customs), and 俗語 (zokugo, slang)

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Readings from KANJIDIC2, © EDRDG, CC BY-SA.