牛 is a front-view pictograph of a cow's head — two horns rising on either side, the face line down the middle. The oracle bone form was even more schematic: a Y-shaped head with a single vertical stroke for the snout. As a radical, 牛 anchors a category of "cattle / domestic animal / generic object" characters: 牧 (mù, to herd — cow plus a hand holding a whip), 物 (wù, thing — cow plus color markings; this character generalized from "spotted cow" to "all things in the world"), 特 (tè, special — originally a castrated bull, then "exceptional / particular"), 犠 (xī, sacrifice — a sacrificial ox in ritual).

Korean reading "u." 牛乳 (uyu, milk — note Korean uses Sino-Korean for milk, while Japan does too), 牛肉 (uyuk, beef — though native 소고기 dominates daily speech), 牛馬 (uma, "cattle and horses" = beasts of burden), 韓牛 (hanu, "Korean beef" — a culinary heritage brand and one of the most prized food categories in Korean cuisine), 黃牛 (hwangu, yellow ox — the traditional Korean breed). 한우 is one of the most charged words in modern Korean food culture.

Mandarin niú, 2nd tone. 牛肉 (niúròu, beef), 牛奶 (niúnǎi, milk), 牛仔 (niúzǎi, cowboy / jeans — 牛仔裤 niúzǎikù = jeans). 黄牛 (huángniú) has a fascinating second meaning: in modern Mandarin slang, it means "ticket scalper" — referencing how scalpers loiter outside venues like patient oxen waiting for prey. Internet slang elevated 牛 itself to a powerful compliment: 牛人 (niúrén) = "an awesome person," 很牛 (hěn niú) = "really cool / impressive" — the bull's strength as metaphor for excellence.

Japanese on-reading ギュウ (gyū) — 牛肉 (gyūniku, beef), 牛乳 (gyūnyū, milk — note both meanings carry the gyū sound, building the "cow" word naturally into Japanese dairy and meat vocabulary), 闘牛 (tōgyū, bullfighting). The signature dish 牛丼 (gyūdon, "beef-bowl") — thinly sliced beef simmered with onions over rice — is a fast-food cornerstone of Japanese daily eating, served by chains like Yoshinoya and Sukiya. Kun-reading うし (ushi) — 牛 (ushi, cow), 子牛 (koushi, calf).

Memory aid: a Y-shaped head with horns on either side. Look at the top of 牛 — those two horns are unmistakable.