From Teflpedia
Disambiguation: see -ability for the suffix. See also language proficiency.

Ability (/əˈbɪləti/) is the capacity of having the means or skill to do something.[1]

In English, ability is often expressed using the full modal verb "can", and its preterite "could". It's also possible to use the lexical-grammatical structure "be able to", particular as an infinitive (i.e. "to be able to") or as a gerund "being able to", since being a full modal verb "can" lacks an infinitive and gerund.

For someone (e.g. a child) who is subordinate to another person (e.g. an adult), ability is often strongly associated with permission. e.g. Hence a child will ask "can I watch a cartoon?" when they mean "Will you give me permission to watch a cartoon that I would like to watch?"