一定

• Pinyin: yī dìng
• Hanzi breakdown: 一 = single horizontal stroke meaning 'one'; 定 = 宀 (roof) + 疋 (foot), meaning 'to settle/fix'

Meaning

Certainly; definitely; must. Expresses strong certainty, determination, or a fixed requirement.

Used to express firm belief, strong promises, or necessary conditions. As an adverb it means 'definitely/certainly,' as an adjective it means 'fixed/certain.' Often used to make promises or express confident guesses. One of the most common ways to show determination in Chinese.

Examples

1. 明天我一定来。 I will definitely come tomorrow.
2. 你一定要好好学习。 You really must study hard.
3. 他一定是忘了。 He must have forgotten.

Usage Guide

Context: promises, certainty, requirements

Tone: emphatic

Do Say

• 我一定会帮你的。(I will definitely help you.)
• 去北京一定要看长城。(You absolutely must see the Great Wall when you go to Beijing.)

Don't Say

• 一定可能会下雨。(Don't combine 一定 with 可能 — they contradict each other. Use 一定会下雨 for certainty or 可能会下雨 for possibility.)

Origin & History

Compound of 一 (one/single) + 定 (fixed/settled). Literally 'singularly fixed,' conveying absolute certainty and determination.

Cultural Context

Generation: All ages

Social background: Universal