The meaning of COULD is —used in auxiliary function in the past, in the past conditional, and as an alternative to can suggesting less force or certainty or as a polite form in the present. How to use …

COULD definition: 1. past simple of "can", used to talk about what someone or something was able or allowed to do…. Learn more.

Could is also used to talk about ability in the present, but it has a special meaning. If you say that someone could do something, you mean that they have the ability to do it, but they don't in fact do it.

You use could to talk about a possibility, ability, or opportunity that depends on other conditions. Their hope was that a new and better East Germany could be born.

We use could have to say that someone had the ability or opportunity to do something, but did not do it: She could have learned Swahili, but she didn't want to.

The English modal auxiliary verbs are a subset of the English auxiliary verbs used mostly to express modality, properties such as possibility and obligation. [a] They can most easily be distinguished from …

"Could" is a modal verb used to express possibility or past ability as well as to make suggestions and requests. "Could" is also commonly used in conditional sentences as the conditional form of "can."