Several parts combine into one character.

限 is a phonetic-semantic compound: 阝 (the "mound / hill" radical, when written on the left) + 艮 (gèn, "to stop / look back"). 艮 supplies both the sound and the meaning of "stopping / coming up against." The composite reads as "the place at the hill where one stops" = a boundary, a limit, the point where motion ceases.

Korean reading "han." 限界 (hangye, limit — used physically and metaphorically: "limit situation," 한계점 "breaking point"), 制限 (jehan, restriction), 限定 (hanjeong, limitation / specifying), 期限 (gihan, deadline / time limit), 有限 (yuhan, finite — math term), 無限 (muhan, infinite — math and philosophy: 무한대 muhandae "infinity"). Korean mathematics, law, and contract vocabulary depends on 한.

Mandarin xiàn, 4th tone. 限 (xiàn), 限制 (xiànzhì, restriction), 界限 (jièxiàn, boundary), 有限 (yǒuxiàn, finite / limited — used in 有限公司 "limited liability company"), 无限 (wúxiàn, infinite), 期限 (qīxiàn, deadline / term), 限量 (xiànliàng, limited quantity — common marketing term: 限量发售 limited release).

Japanese on-reading ゲン (gen) — 制限 (seigen, restriction), 限界 (genkai, limit), 限定 (gentei, limitation — used in 限定品 genteihin "limited-edition item," major Japanese marketing concept), 期限 (kigen, deadline / expiration date — printed on every food package: 賞味期限 shōmi kigen "best-by date," 消費期限 shōhi kigen "use-by date"). Kun-reading かぎる (kagiru, "to limit / restrict") — 限る (kagiru), 限り (kagiri, limit / extent). The polite formal expression ~に限り (~ ni kagiri, "limited to ~") appears in announcements: 本日に限り 30% off ("today only, 30% off").

Memory aid: hill (阝) where one stops (艮) — the boundary at the foot of an obstacle.