1.
formula; mathematical expression; equation
A mathematical expression or formula — a written combination of numbers, variables, and operators. Used in mathematics, physics, chemistry, and other technical fields.
この式を解いてください。
Please solve this equation.
答えだけでなく式も書いてください。
Please write the formula too, not just the answer.
先生は黒板に長い式を書いて説明した。
The teacher wrote a long formula on the blackboard and explained it.
2.
ceremony; formal event
A formal ceremony or ritual occasion. Often appears as a suffix on the names of specific ceremonies (e.g. 結婚式 wedding ceremony, 卒業式 graduation ceremony).
式が始まります。
The ceremony is about to begin.
式には大勢の人が出席した。
A large crowd attended the ceremony.
娘の卒業の式でつい涙が出てしまった。
I couldn't help shedding tears at my daughter's graduation ceremony.
Two main uses share the same kanji: a math/science formula, and a formal ceremony.
SENSE 1 — FORMULA:
- 方程式: equation
- 計算式: calculation formula
- 化学式: chemical formula
- 式を立てる: to set up a formula
- 式を解く: to solve an equation
SENSE 2 — CEREMONY:
Very often used as a suffix attached to the type of event:
- 結婚式: wedding ceremony
- 卒業式: graduation ceremony
- 入学式: school entrance ceremony
- 葬式: funeral
The standalone noun 式 usually refers to whichever ceremony is salient in context.