郵送
ゆうそう · yuusou · JLPT N2 · noun
mailing
📮 郵 = postal mail + 送 = send, so 郵送 = send by mail
郵 is the character for postal mail, and 送 means to send or deliver. Put together, they mean sending something through the post.
送 — 辶 (walk) + 关 (simplified from 灷, fire/torch)
Originally depicted hands holding a torch to escort someone on a journey, combined with the 'walk' radical 辶. The right side 关 is a simplification of an older form showing fire being carried. The core meaning evolved from 'escort/see off' to the broader sense of 'send' or 'give as a gift.'