1. In electronics, a diode is a two-terminal electronic component that conducts primarily in one direction (asymmetric conductance); it has low (ideally zero) resistance to the current in one direction, and high (ideally infinite) resistance in the other. A semiconductor diode, the most common type today, is a crystalline piece of semiconductor material with a p–n junction connected to two electrical terminals.
2. A diode is an electrical component designed to conduct electric current in only one direction. It has two ends (or terminals), each with an electrode of a different charge. The "anode" end has a positive charge relative to the negatively charged "cathode" end. Current naturally flows in the direction from the anode to the cathode.
https://en.wikipedia.org/wiki/Diode (1.); https://techterms.com/definition/diode (2.)