What is 35mm Film?
An antique memory-card (read:canister) used by people before the invention of flash memory. The canisters held very few images (twenty-four, or, sometimes, thirty-six), and the only card readers were very expensive, so people usually had to have the cards read at Photo-Labs. The process of reading the cards was called "developing", and only late in the game would be provided in a digital form; usually you had to scan the photos in from the paper copies.
John: Where does the memory card go in this camera Mom?
Jane: That's a 35mm film camera...
John: What's 35mm film? I've never even heard of that memory card.