The difference between “blond” and “blonde” has escaped me for many years now. Finally, I looked it up and the difference will never me. It also makes for a good discussion/argument (depends on how you look at it or how defensive someone gets) in creative writing classes.
So, I digress…
“Blond” and “blonde” are spelled differently because they have two different meanings.
Refers to the color! People have “blond” hair, golden retrievers have “blond” fur, that paint looks “blond,” etc.
Refers specifically to a female with blond hair. Therefore, my cousin is a “blonde” because she has blond hair.
Here’s the catch…
A male with blond hair is a “blond.” “Blonde” only is used when referring to females.
What if it's plural?
From what I have seen. If you are making it plural. You use "blonds" when referring to a group of males and "blondes" when referring to a group of females, or a group of males and females.
Because of the female/male catch, some people believe that “blonde” is a sexist term and will not use that spelling. They spell everything as “blond.” So, I guess, if you are ever unsure, just use “blond” in all instances. However, if you want to be technically correct, differentiate appropriately.