Phase - Classification of an ac circuit usually single-phase, two wire or three wire; two-phase, three wire or four wire; or three-phase, three wire or four wire.
Pigtail - A short, added piece of wire connected by a wire nut. Commonly used to extend or connect wires in a box.

Romex - A brand name of nonmetallic-sheathed cable made by General Cable Corporation. Often mistakenly used as a collective term for NM sheathed cable.
Rough-In - Installing the boxes, cables, and making "in-wall" connections while the walls are still open. Later, final connections are made and the devices and appliances are installed during the trim-out.