Anode
Definition
The electrode where oxidation happens. Remember An Ox: Anode = Oxidation.
Technical definition
The anode is the electrode at which oxidation occurs in an electrochemical cell. In galvanic cells it is the negative electrode, while in electrolytic cells it is the positive electrode: the sign flips, but oxidation always happens at the anode.
Example
In a Daniell cell, the zinc electrode is the anode: zinc metal oxidizes to Zn^2+, releasing electrons into the wire.
Common confusion
The anode is NOT always negative. In a galvanic (battery) cell it is negative, but in an electrolytic cell, like electroplating, the anode is positive. Anode = oxidation is the rule that never changes.