Why do they call it homeschooling?

Yesterday: park, then three stores to find scooter, roller skates, and toy golf clubs.
Today: long walk to scooter and skate on a street with sidewalks, different park, gymnastics class.
Tomorrow: play date at yet another park.
Day after tomorrow: Gamer Day at a house across town.(Oh wait, that one will be at someone else's home. ;-)