Two-fer

The name for a cable assembly used for combining multiple lighting instruments into one circuit.

It has two female ends and one male end thus allowing you to get "Two for One." Sometimes also known as a "Y" cable, especially if of the molded type,

http://www.lexproducts.com/cs/Entert...oductLineId=17

although "V" style, where the two female legs both enter the male connector is more common.

http://www.4wall.com/1-cable.php

Sometimes spelled as "tufer" and/or abbreviated "2F".

Any connectors commonly used for lighting power can be used on a twofer: stagepin twofer, Edison twofer, L6-20 twofer, even Socapex twofer.http://www.rubberbox.co.uk/on-the-shelf/splitters/RUBSOC2.php. Using different males than females thus doing double-duty as an adapter as well as splitter, may be expedient but should be discouraged.

From Lex Products website:

Two-Fer (National Electric Code Definition). An adapter cable containing one male plug and two female cord connectors used to connect two loads to a branch circuit.