What is "potassium channel"

n. (context biology English) A small pore in a cell membrane that is selective to potassium ions and has several regulatory functions.

In the field of cell biology, potassium channels are the most widely distributed type of ion channel and are found in virtually all living organisms. They form potassium-selective pores that span cell membranes. Furthermore potassium channels are found in most cell types and control a wide variety of cell functions.