What is an slot on a motherboard used for?

Nowadays, it is widely used for magnetic hard drives and SSDs in format as well as for the slot In the case of SSDs, it is

2: one with a B key and one with a M key to PCI-E x4 adapter that can take multiple lengths of drives socket types B+M keyed

m2 slot types Two types of PCIe slot on an Asus H81M-K motherboard Various slots on a computer motherboard, from top to bottom: PCI Express x4; PCI Express x16; PCI Express

m2_1 slot 2 expansion card to add an additional Slot to your PC ATX motherboards have ample slots but if you have a small form factor mATX motherboard (usually