Yeah, I interpret "cinematic," as anything that has inherent movie-like qualities. Even in gameplay sequences. There was a big like five part retrospective/analysis of the Uncharted series on Youtube (forget the name of the channel) but it shed some light on how the gameplay of like Uncharted 2 for example is super linear, but framed in a lens like you have a thousand choices to handle a problem when the developers may intend or only allow a couple. The tank sequence in Tibet was the example given.
I'd say cinematic would refer to the player character almost stepping into the role of the main actor in a game's events. Everything in the game, including options available, are included to reinforce the story. Snake is sneaking past guards to get into a fortress. The gameplay itself is representative of the storyline. Compared to most open world games or JRPGS.
You never hear about Edward Kenway's heroic plundering of uncharted islands for a chest with 250 reales or the time he spent agonizing over whether he needed to reinforce the Jackdaw's hull or add cannons. The story doesn't reference all the Grangalan Jr. Jr.'s Cloud had to kill to get to the Gold Saucer. These instances are treated more like novels. Tolkien spending six pages describing the forest on the way to Huckleberry Ferry is equivalent to traveling the overworld in these games.
Whereas cinematic games usually lack chaff, or emergent world building for the sake of concise experiences. I don't want to say the term is interchangeable with "linear," because there's some cinematic open world games and some linear games that aren't cinematic at all (Soulsborne, etc)