discrimination

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

• noun The act of discriminating.
• noun The ability or power to see or make fine distinctions; discernment.
• noun Treatment or consideration based on class or category, such as race or gender, rather than individual merit; partiality or prejudice.

from The Century Dictionary.

• noun The act of distinguishing; the act of observing, making, or marking a difference; distinction: as, the discrimination between right and wrong.
• noun Specifically The power of distinguishing or discriminating; discriminative judgment; penetration: as, a man of discrimination.
• noun The state of being discriminated, distinguished, or set apart.
• noun That which serves to discriminate; a mark of distinction.
• noun Specifically An invidious distinction.
• noun Synonyms Discernment, clearness, acuteness, acumen, nicety, insight. See difference and discernment.

from the GNU version of the Collaborative International Dictionary of English.

• noun The act of discriminating, distinguishing, or noting and marking differences.
• noun The state of being discriminated, distinguished, or set apart.
• noun (Railroads) The arbitrary imposition of unequal tariffs for substantially the same service.
• noun The quality of being discriminating; faculty of nicely distinguishing; acute discernment.
• noun That which discriminates; mark of distinction.

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

• noun a distinction; discernment, the act of discriminating, discerning, distinguishing, noting or perceiving differences between things.
• noun The state of being discriminated, distinguished from, or set apart.
• noun distinct treatment of an individual or group to their disadvantage; treatment or consideration based on class or category rather than individual merit; partiality; prejudice; bigotry
• noun The quality of being discriminating, acute discernment, specifically in a learning situation; as to show great discrimination in the choice of means.
• noun That which discriminates; mark of distinction, a characteristic.

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

• noun the cognitive process whereby two or more stimuli are distinguished
• noun unfair treatment of a person or group on the basis of prejudice