I learned a new word today:
"retronym"
When you rename something to define a difference in a noun which is no longer unique.
Example:
guitar
became
acoustic guitar, electric guitar, bass guitar and so on, whereas before electric guitars even existed, the acoustic guitars were just called "guitars".
Most of the time it's when there's a change in technology,
"Computer"
became
Mainframe, Mini Computer, Microcomputer,
then later
Desktop Computer, Laptop Computer, Handheld Computer
but sometimes with social change. As more men go into formerly female dominated professions and more women go into formerly male dominated professions. "Male nurse" or other distinctions made people who need to define the gender of a profession see the need for. "Oh, she has a male secretary." "Uh, why not just call him a 'secretary'". "Woman Cop" "Female Fire Fighter".
(I've even heard "Male Masseur" which is ridiculous, because the term, in French, is defined by gender anyway. A masseur is male, a masseuse* is female, a MASSAGE THERAPIST can be whatever s/he wants to be. Sorry, off-topic rant over...)* Remember the "Just doesn't matter" scene in Meatballs? "Not masseur, masseuse!")
Here's a list: