一会儿
yīhuìr · HSK 1
moment
⏳ 一 (one) + 会儿 (short while) = one little while = a moment
会 here means a brief span of time, and the 儿 suffix adds a casual northern-Mandarin diminutive feel. So 一会儿 literally stacks 'one + short-while' to mean 'a moment' or 'in a little bit'.
一 — single horizontal stroke
一 is one of the simplest pictographs in Chinese, depicting a single horizontal line to represent the number one. It has retained essentially the same form since oracle bone script over 3,000 years ago. By extension it also means 'first,' 'whole,' or 'same.'
会 — 人 person on top + 云 cloud/say below (simplified from 會)
The traditional form 會 showed a lid over a vessel with contents stacked inside, depicting things coming together — hence 'meet, gather, assemble.' From 'gathering' it extended to 'meeting,' then 'understand' (minds meeting) and 'be able to.' The simplified 会 keeps only a schematic top and bottom.