From the point of view of my little brain it seems that just saying entry level bike without saying what it’s an entry level into just has no meaning.

An entry-level Cyclocross bike would be the lowest level offering that you could expect to be able to survive and function on a racecourse. Not that you are going to race it but that it could survive out there.

A department store “Mtn. Bike” will not survive real off road use so it is NOT an entry-level Mountain Bike but it might be an entry level urban cruising bike.