公式
gōng shì · HSK 5
formula
📐 公 (public) + 式 (pattern) = a public/official pattern, i.e. a formula
公 means public or official; 式 means pattern, style, or ceremony. Together they name a standardized public pattern — a formula or official format. Same 式 appears in 方式 (method) and 式样 (style).
公 — eight 八 + private 厶
Originally an ideograph showing 八 (to divide) over 厶 (private/self), depicting the act of splitting away from selfish interest. The combination came to mean 'public' or 'fair,' the opposite of private. It later extended to senses like 'duke,' 'lord,' and 'grandfather.'
式 — 工 (work) + 弋 (phonetic)
式 is a phono-semantic compound: 工 ('work, craft') gives the meaning of a tool, rule, or method, while 弋 supplies the sound. It originally referred to a standard pattern or model used in craftsmanship, then broadened to mean 'style, form, ceremony, or formula.'