有效 (yǒuxiào)

有效 describes something that produces the desired result or is legally in force.

Meanings

[adjective] Effective; producing the intended result.
[adjective] Valid; legally or officially in force.

Example Sentences

这种方法非常有效。 Zhè zhǒng fāngfǎ fēicháng yǒuxiào. This method is very effective.

你的护照还有效吗？ Nǐ de hùzhào hái yǒuxiào ma? Is your passport still valid?

这个药对感冒很有效。 Zhège yào duì gǎnmào hěn yǒuxiào. This medicine is very effective against colds.

签证的有效期是三个月。 Qiānzhèng de yǒuxiào qī shì sān gè yuè. The visa is valid for three months.

Collocations

Collocation	Meaning
有效期	validity period; expiry date
有效方法	effective method
有效措施	effective measure
切实有效	practical and effective
长期有效	valid for a long time

Usage Notes

有效 can describe both practical effectiveness (a plan works) and legal validity (a document is still in force). When discussing documents, 有效期 (validity period) is a very common compound. Do not confuse with 效果 (effect/result), which is a noun.

Memory Hook

有 means "to have" and 效 means "effect" — if you "have effect," you are effective.