Hot Swap - definition

Hot swap is the feature to add and modify a component in a computer system without shutting it down or pausing its on-going activity. Nowadays more or less most of the mobile devices come with feature so that SIM card or removable SD card can be inserted / ejected while the device is in operating mode.
Also, it is another most used feature in Mechanical Keyboards. The mechanical keyboard which supports Hot Swap function, the key switches can be changed/altered/modified while the device is in operating condition.