盛开
shèng kāi · HSK 7
in full flower
🌸 盛 abundant + 开 open = flowers opening in abundance, full bloom
盛 means flourishing or abundant; 开 means to open. Together they describe flowers that have opened to their fullest, so 盛开 is the peak-bloom stage when a plant is covered in open blossoms.
盛 — 成 (chéng, phonetic) + 皿 (vessel)
A phono-semantic compound: 皿 (a dish or vessel) gives the meaning, while 成 supplies the sound. The original sense was grain heaped into a ritual vessel as an offering, hence 'to fill' or 'contain' (chéng). From 'full to the brim' it extended to 'abundant, flourishing, prosperous' (shèng).
开 — two hands 廾 + door 门 (open gate)
Originally written 開, showing two hands (廾) lifting the bar (一) off a gate (門) to open it. The simplified form 开 keeps the two-hands element and drops the gate. Core meaning 'to open' extended to 'start, operate, bloom'.