一会儿

一会儿 (yíhuìr) is a flexible time word meaning 'a short while' — it covers both a brief duration ('for a little while') and a near-future moment ('in a moment, shortly'). Two main uses. First, as a future time marker AT the start of a clause: 一会儿见 ('see you in a bit'), 我一会儿来 ('I'll be there in a moment'). Second, after a verb to mark a brief duration: 等一会儿 ('wait a moment'), 休息一会儿 ('rest for a bit'). The doubled structure 一会儿...一会儿... means 'one moment X, the next moment Y' — describes alternating states: 一会儿哭一会儿笑 ('crying one moment, laughing the next'). The 儿 is a Beijing-flavored suffix and gets the syllable rolled into yíhuìr — in writing or southern speech, 一会 (without 儿) is fine. Tone change: 一 becomes second-tone (yí) before the fourth-tone 会 (huì).

Note: Highly colloquial, especially the 儿-suffixed form. In southern Mandarin and in writing, the form 一会 (without 儿) is more common.

Memory hook: 一 ('one') + 会 ('moment / meeting') = one brief moment. The 儿 just adds a casual Beijing flavor.