回升
huíshēng · HSK 7
rise again
📈 回 (return) + 升 (rise) = rise back up — a rebound after a dip
回 — enclosure 囗 + smaller 囗 inside
回 is a pictograph of a swirling whirlpool or coiled spiral, shown as nested squares in modern form. The original meaning was 'to revolve' or 'turn around,' which extended to 'return' and 'a time/occurrence.' It also appears as a phonetic in characters like 茴 and 廻.
升 — ladle/scoop pictograph (related to 斗)
升 originally pictured a ladle or dipper used to measure grain, closely related to 斗 (a larger dipper). It came to denote a unit of dry measure (a 'sheng', about a liter). From 'scooping up' it extended to the meaning 'rise, ascend'.