When is an ios game a board game?

I’ve been thinking about the games on my iPad. I think of some as board games and others as not board games. Games that were originally board games are almost automatically considered board games. Adventure/ point and click/ dexterity games are not. But is that what makes a game a board game; that it is not a dexterity game or could easily be implemented as a physical game?

Example games:

Board Games:
Agricola
Patchwork
Cthulhu Realms
Carcassonne
Twilight Struggle (still need to learn this one)
Galaxy Trucker - even though it has some quick play at the beginning

Not Board Games:
Alto’s adventure
Sorcery
Osmos
Tentacle Wars
Monument Valley
XCOM
Minecraft
Blockwick
Dwelp
Aqueduct
The Room
Quell
Waking Mars

Board Games or not?
Haunted Hollow
Card Crawl - could be implemented as a card game
Space Food Truck - could also be implemented as a card game
Heartstone - could be implemented as a card game
Solitairica