wvpr: A pass is a card or ticket to gain access to something. For example, you could get a season pass for sports events, plays, concerts, museum exhibits, or amusement parks. You would use the pass to enter as often as you liked instead of buying a new ticket each time. A season pass is usually cheaper than individual ticket costs, and it can include other advantages like guaranteed entry.

Episodic games and DLC have been marketed as seasons, probably because of the similarity to episodic television seasons. From there it's easy to see the connection to season passes. A season pass to a game gets you an arbitrary season worth of pre-planned future content.

Telltale chose to call this offering an adventure pass, maybe to distinguish it from a previous season pass or remove expectations that it will last for a year. Or they just liked the sound of it. I don't know the reason for the name change, but the adventure pass serves the same purpose as the season passes available for other games. They could have called it a pack, but the episodes aren't finished yet, so they can't put them all into a finished bundle. Pass implies you're paying for something ongoing rather than a completed set.

shmerl: Thanks, that explains the wordplay and connections very well. I never really bought games with "season passes" before, so I didn't understand the connection in "adventure pass" (which is secondary to the first wordplay already, which makes it even less sensible at the face value).

I'd say original wordplay isn't a very good match though. Season pass like in the case of ticket implies some time limited access, which expires once that season is over. Here it means simply buying something in advance, and getting it once it's released gradually. So something like season pre-order / episodic pre-order would be much more descriptive.