"item slots" refers to the spaces available for items in a specific game or system. These slots determine the number of items or objects a player can carry or equip at any given time. Full definition
I have noticed that your games have fewer item slots. (zeboyd.com)
You've got thirty - two item slots so you likely shouldn't run of space at any time. (gamergeddon.com)
While weapons level up on a per usage basis, allied characters are given five item slots for equipment such as weapons, armor, and items - helping to even the odds of the game's more challenging encounters. (tech-gaming.com)