What is the control electrode in a field-effect transistor?

In a Field-Effect Transistor (FET), the three primary terminals are the source, drain, and gate. The gate is the terminal used to control the flow of charge carriers between the source and the drain. Applying a voltage to the gate creates an electric field that alters the width of the conducting channel, thereby regulating the current. This makes it the true "control" electrode of the device. The "base" is the control electrode in a Bipolar Junction Transistor (BJT), not an FET. The "source" and "drain" are the terminals through which the main current flows, analogous to the emitter and collector in a BJT.