届く is written with the kanji 届, which combines 尸 (a body or corpse radical, suggesting something prostrate or extended) and 由 (reason, origin). The character originally conveyed the idea of something stretching out to its full extent — naturally giving rise to meanings of physically reaching something or, by extension, a delivery arriving at its intended place.

In Japan, the concept of 届く carries emotional weight beyond physical delivery. The phrase 気持ちが届く (kimochi ga todoku) — "one's feelings reach [someone]" — is a common and heartfelt expression in songs, literature, and everyday speech. The idea that sincerity or care must "arrive" at another person's heart reflects a cultural value placed on genuine emotional communication. You'll also encounter 届け (todoke), the noun/imperative form, in famous song titles and anime, often used as a passionate call: "reach me!" or "let this get through!"