Know how to use "fewer" and "less"? Find out.
1640s, "the making of distinctions," from Late Latin discriminationem (nominative discriminatio), noun of action from past participle stem of discriminare (see discriminate). Especially in a prejudicial way, based on race, 1866, American English. Meaning "discernment" is from 1814.
It especially annoys me when racists are accused of 'discrimination.' The ability to discriminate is a precious facility; by judging all members of one 'race' to be the same, the racist precisely shows himself incapable of discrimination. [Christopher Hitchens]
in psychology, the ability to perceive and respond to differences among stimuli. It is considered a more advanced form of learning than generalization (q.v.), the ability to perceive similarities, although animals can be trained to discriminate as well as to generalize.