Several parts combine into one character.

脈 is a semantic compound: 月 (flesh radical) + 𠂢 (a stylized branching shape, "tributaries / branches"). The character pictures "branching flows inside the body = blood vessels, the pulse." From this anatomical root, 脈 extended metaphorically to "any branching trunk-like thing" — mountain ranges, family lineages, narrative threads, professional networks. One of the most productive metaphor-engines in CJK vocabulary.

Korean reading "maek." 脈搏 (maekbak, pulse — medical), 動脈 (dongmaek, artery), 靜脈 (jeongmaek, vein), 山脈 (sanmaek, mountain range), 人脈 (inmaek, "people-veins" = personal network / connections), 文脈 (munmaek, "text-veins" = context / narrative thread). 인맥 in Korean business culture is a serious career concept — building one's 인맥 across companies, schools, and hometowns is treated as a measurable professional asset.

Mandarin mài, 4th tone. Simplified form 脉 — 脉 (mài), 脉搏 (màibó, pulse), 静脉 (jìngmài, vein), 人脉 (rénmài, personal connections / network), 山脉 (shānmài, mountain range). Identical metaphorical reach to Korean. 人脉 dominates Chinese business-school vocabulary as the explicit name for what English calls "networking."

Japanese on-reading ミャク (myaku) — no kun reading in common use. 脈 (myaku, pulse), 脈拍 (myakuhaku, pulse rate), 動脈 (dōmyaku, artery), 人脈 (jinmyaku, personal network — major Japanese business term: 人脈を作る jinmyaku o tsukuru, "to build connections"), 山脈 (sanmyaku, mountain range). Japanese corporate culture treats 人脈 as a measurable career asset, much like LinkedIn-era Western "network" — but with longer cultural roots, since the metaphor itself is 2,000 years old.

Memory aid: flesh (月) plus a branching flow (𠂢) — the body's branching streams, then any branching trunk in the world.