外形
wài xíng · HSK 7
external form
📐🔷 外 (outer) + 形 (form) = the outer form, i.e. shape or contour
外 means outside or external; 形 means form or shape. Together 外形 is the external form of a thing: its figure, contour, or overall shape. Same 形 appears in 形状 (shape) and 图形 (figure).
外 — evening 夕 + divination 卜
Originally a compound of 夕 (evening) and 卜 (divination). Ancient Chinese divinations were performed in the morning; doing them at evening (夕) was considered irregular or 'outside' the norm. From this sense of deviation, 外 came to mean 'outside' or 'external'.
形 — open frame 开 + hair/pattern 彡
形 combines 开 (originally a phonetic element suggesting the sound) with 彡, a radical depicting fine lines, hair, or decorative strokes. The 彡 part conveys the idea of visible markings or surface appearance, giving 形 its core meaning of 'shape' or 'form.' Over time it broadened to cover physical figure, appearance, and abstract form.