Real Dictionary

hear
If you have heard of something or someone, you know about them, but not in great detail.
If you say that you can hear someone saying something, you mean that you are able to imagine hearing it.
verb: If you hear from someone, you receive a letter, email, or phone call from them.
verb: If you hear some news or information about something, you find out about it by someone telling you, or from the radio or television.
verb: If you hear something such as a lecture or a piece of music, you listen to it.
verb: In a debate or discussion, if you hear from someone, you listen to them giving their opinion or information.
verb: When a judge or a court of law hears a case, or evidence in a case, they listen to it officially in order to make a decision about it.
verb: When you hear a sound, you become aware of it through your ears.

hear in American English
to perceive or sense (sounds), esp. through stimulation of auditory nerves in the ear by sound waves
intransitive verb: to be capable of perceiving sound by the ear; have the faculty of perceiving sound vibrations
transitive verb: to perceive by the ear

hear in British English
verb: to perceive (a sound) with the sense of hearing