No it's not the correct word to use here, what year is that book from? We are not separated enough to be considered a different race, Biologically Race Doesn't Exist In Humans.Lionsfan said:A definition from an anthropology book:
Ethnic Group: Group distinguished by cultural similarities (shared among members of that group) and differences (between that group and others); ethnic group members share beliefs, customs, and norms and, often, a common language, religion, history, geography, and kinship.
For the question you're asking (skin color), race is the correct term here. Yes, as humans we're all very similar, so it's not a different dog breed type of thing, but there are differences between the groups involving small barely noticeable things like bone growth.
Ethnicity is social, race is biological
"Race is a real cultural, political and economic concept in society, but it is not a biological concept, and that unfortunately is what many people wrongfully consider to be the essence of race in humans -- genetic differences," Templeton said. "Evolutionary history is the key to understanding race, and new molecular biology techniques offer so much on recent evolutionary history. I wanted to bring some objectivity to the topic. This very objective analysis shows the outcome is not even a close call: There's nothing even like a really distinct subdivision of humanity."
Source
http://wupa.wustl.edu/record_archive/1998/10-15-98/articles/races.html
http://www.scienceagogo.com/news/19980909040042data_trunc_sys.shtml
http://www.press.uchicago.edu/ucp/books/book/distributed/S/bo3622374.html
As for Ethnicity I'm using the adjective definition not the noun definition.
dictionary.reference.com
ethnic or ethnical
? adj
1. relating to or characteristic of a human group having racial, religious, linguistic, and certain other traits in common
2. relating to the classification of mankind into groups, esp on the basis of racial characteristics
merriam-webster
2
a : of or relating to large groups of people classed according to common racial, national, tribal, religious, linguistic, or cultural origin or background
So you can use ethnicity to to describe race, but race is technically wrong. You are right tho I could of used a better term but I honestly can't think of one.