English Dictionary

opt-in

adj

The property of having to choose explicitly to join or permit something; a decision having the default option being exclusion or avoidance; used particularly with regard to mailing lists and advertising.

The opt-in feature allows users to receive notifications.

意味（1）

The property of having to choose explicitly to join or permit something; a decision having the default option being exclusion or avoidance; used particularly with regard to mailing lists and advertising.

They set up an opt-in mailing list, so that those who wanted the notices could subscribe.