(しき)

しき
noun
formula; expression; equation; ceremony
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(しき)()いてください。
Please solve this equation.
(こた)えだけでなく(しき)()いてください。
Please write the formula too, not just the answer.
先生(せんせい)黒板(こくばん)(なが)(しき)()いて説明(せつめい)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(けっこんしき) wedding ceremony, 卒業式(そつぎょうしき) graduation ceremony).
(しき)(はじ)まります。
The ceremony is about to begin.
(しき)には大勢(おおぜい)(ひと)出席(しゅっせき)した。
A large crowd attended the ceremony.
(むすめ)卒業(そつぎょう)(しき)でつい(なみだ)()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(ほうていしき): equation
  • 計算式(けいさんしき): calculation formula
  • 化学式(かがくしき): chemical formula
  • (しき)()てる: to set up a formula
  • (しき)()く: to solve an equation

SENSE 2 — CEREMONY:

Very often used as a suffix attached to the type of event:

  • 結婚式(けっこんしき): wedding ceremony
  • 卒業式(そつぎょうしき): graduation ceremony
  • 入学式(にゅうがくしき): school entrance ceremony
  • 葬式(そうしき): funeral

The standalone noun (しき) usually refers to whichever ceremony is salient in context.