noun
external form; outer shape; externals
Refers to the outward physical shape or appearance of something, often contrasted with inner content or structure.
この機械の外形はシンプルだが、内部は複雑だ。
The external form of this machine is simple, but the inside is complex.
外形だけでは品質は判断できない。
You can't judge the quality from the outer shape alone.
Compound of 外 (outside) and 形 (shape, form). The reading がいけい is the standard on'yomi combination.