An input socket refers to a place where you can connect something, like a cable or a device, to a computer or electronic device so that it can receive information or signals. Full definition
Parameter steering, Speedtronic cruise control, Audible lights on warning, Boot open warning light, Digital clock, Lights on warning, Outside temperature display, Parking brake warning, Service interval indicator, Trip computer, Auxiliary input socket in glovebox. (whatcar.com)
And they tested the technology on a tiny slice of an adult mouse's neocortex, gaining new insights into the complex relationship between axons (nerve fibers) and dendrites (branches on neurons that act kind of like electric input sockets). (newatlas.com)
Some radios have a power input socket for mains adapters, mine did but it was an odd size (Sony). (treehugger.com)