1a. Receptor for circular or spherical shaped object: Shoulder socket, socket wrench. 1b. Type of wrench where the nut is completely encapsulated, see also ratchet. 2. A lampholder that conducts electricity to a lamp as well as provides mechanical support. The E26, medium screwbase is the most common in the US. E26, E27 bulb socket DB-E26-1 lamp holder 3. In British, synonymous with receptacle.