効力

• Reading: こうりょく
• Romaji: kouryoku
• Kanji breakdown: 効 (kō) — effect, efficacy; 力 (ryoku) — power, force
• Pronunciation: /koː.ɾʲo.kɯ/

Meaning

Effect; efficacy; validity; the power of something to produce a result.

A noun describing the power or effectiveness of something, particularly in legal, medical, and regulatory contexts. Often used for the validity period of contracts, laws, or medicines. Common phrases: 効力がある (to be in effect), 効力を失う (to lose effect), 効力を発揮する (to exert effect), 法的効力 (legal effect).

Examples

1. この契約は来月から効力を発揮する。 This contract takes effect next month.
2. 薬の効力が切れてきたのでもう一度飲んだ。 The medicine was wearing off, so I took it again.
3. 署名がないとこの書類には法的な効力がない。 Without a signature, this document has no legal effect.

Usage Guide

Context: legal, medical, contracts

Tone: professional

Origin & History

Compound of 効 (effect, efficacy) + 力 (power, force). Together they describe the power to produce an effect or achieve a result.

Cultural Context

Era: Classical

Generation: Adults

Social background: Universal