Dictionary

(auxiliary verb, defective) To know how to; to be able to.

Example: She can speak English, French, and German.   I can play football.   Can you remember your fifth birthday?

(modal auxiliary verb, defective) May; to be permitted or enabled to.

Example: You can go outside and play when you're finished with your homework.   Can I use your pen?

(modal auxiliary verb, defective) To have the potential to; be possible.

Example: Animals can experience emotions.

(auxiliary verb, defective) Used with verbs of perception.

Example: Can you hear that?.

Something that could happen, or could be the case, under different circumstances; a potentiality.