From Wikipedia: Race is an artificial construct that means what ever we want it to mean:
http://en.wikipedia.org/wiki/Race_(classification_of_human_beings)
Race is a classification system used to categorize humans into large and distinct populations or groups by anatomical, cultural, ethnic, genetic, geographical, historical, linguistic, religious, and/or social affiliation.
*any word* is an artificial construct that means what ever we want it to mean.
There, fixed it for you. Words may be artificial constructs, but we use them to refer to real and measurable things.