"Ethnicity refers to selected cultural and sometimes physical characteristics used to classify people into groups or categories considered to be significantly different from others A race is a biological subspecies click this icon to hear the preceding term pronounced, or variety of a species, consisting of a more or less distinct population with anatomical traits that distinguish it clearly from other races" Information extracted from: http://anthro.palomar.edu/ethnicity/ethnic_1.htm

Race is classification of the human race, usually by genetic similarities passed hereditarily. This is very controversial, categories have changed throughout history, and there is no one way to determine race. Common ways to classify race are by country of origin, skin color, or self-identification. Ethnicity is a cultural identity that has a range of distinctive features, passed by socialization from one generation to another. There are never clear boundaries, cultural or geographic, that mark the limits of ethnic groups, but a group usually shares common culture, language, religion, behaviors.

Race refers to biological descent; skin colour and facial features. Ethnicity describes cultural heritage that includes a shared language, shared traditions, a shared religion, a shared history and sometimes a shared nationality and geography.

I don't think there is much of a difference definition-wise. I think "race" is an old term and tends to have a negative connotation due to all of the historical "racial" crimes..."ethnicity", on the other hand, is a recent term and, therefore, its use is generally thought to be more acceptable.

"Race" refers to the purely physical differences observable between populations that have enough shared genetic characteristics to make distinction between groups apparent. Although we usually use the term in reference to humans, the concept can apply to almost (?) any organism. The foundations of Anthropology as a general study of mankind were laid in the curiosity about man's great variation in physical and behavioral manifestations. Beginning efforts to sort out the mysteries of physical differences resulted in designation of four general stereotypes - white, black, yellow & red; the various 'browns' were correctly calculated to be in-between-somewhere. Big Hairy Deal, Huh? The human inclination to exploration, pillage and indiscriminant breeding usually result in genetic mixture between old populations, especially at territorial fringes Changes in racial characteristics of succeeding generations can be fairly rapid. The term "culture" applies to all of our non-physical customary attributes - how we perceive reality, how we think about it, discuss it, and adapt to it. Race has NOTHING to do with Culture and vice versa, though they can be sufficiently coincidental that one can be inferred by the other at a given point in history. Ethnicity refers to a common culture of a region, often a country, and usually only comes up in reference to geographical transplants to another region. Thus, "German-American" can be an appropriate designation of ethnicity if desired, but the term "African-American"used as a euphemism for a race is totally lame.