absolute pitch

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The precise pitch of an isolated tone, as established by its rate of vibration measured on a standard scale.
• noun Music The ability to identify any pitch heard or produce any pitch referred to by name.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The exact pitch as established by its rate of vibration based on a standard scale.
• noun A perfect pitch; the ability to identify or reproduce any tone heard perfectly.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the ability to identify the pitch of a tone