What is the "other" memory?

The "other" memory is memory that is allocated but that iOS doesn’t categorize into any of the other memory groups. In other words,

Other = Total – Free – Wired – Active – Inactive

This is iOS-specific — on macOS, all the memory is split between the remaining categories and "other" is always 0. Apple does not document what this memory is used for — some say it is used for textures, but I have not seen any confirmation or proof of this claim.

The amount of "other" memory is usually the largest of all the categories, often more than 50% of the total memory.