The term PLUMBING FEATURE is a crossword solution that consists of two words: TRAP (4 letters). A TRAP is a type of plumbing feature that is used to prevent sewer gases from entering a building. It is typically installed in the drain line of a sink, shower, or other fixture. The TRAP is designed to hold a small amount of water, which acts as a barrier to the gases. Traps are an important part of any plumbing system and must be maintained regularly.