As I recall from some marketing class or other - to use a concrete word like Apple, it can't be indicative of the product's function. So the use of the name App

As I recall from some marketing class or other - to use a concrete word like Apple, it can't be indicative of the product's function. So the use of the name Apple for a computer company doesn't in any way restrict other companies from entering that market. But naming something after the offline function that it implements - that does affect other companies trying to enter that market. I.e. if instead of Apple they'd chosen PC Computers - it likely would not have been a valid trademark. And if you were an apple producer and tried to call yourself Apple Inc., sorry that's no good either. IANAL, obviously.