In the context of an electrochemical cell or an electrolytic process, the cathode is generally associated with the electrode where reduction (gain of electrons) occurs. However, it's important to note that the terminology can vary depending on the convention used.
In general scientific and engineering practice, the cathode is considered the negative electrode. This convention is often referred to as the "electrons flow from negative to positive" convention, or the "electrochemists' convention." In this convention, electrons flow from the anode (positive electrode) to the cathode (negative electrode) in an electrochemical cell.
On the other hand, in older or alternative conventions, such as the "conventional current flow" convention, the cathode is considered the positive electrode. This convention assigns the direction of current flow as being from positive to negative, opposite to the actual flow of electrons.
To avoid confusion, it's always a good idea to specify the convention being used when discussing cathodes and anodes.