What is the term used for a bathroom or washroom sink?

The term "lavatory" is commonly used to refer to a bathroom or washroom sink. In plumbing terminology, a lavatory specifically denotes a sink designed for handwashing, typically found in bathrooms. It is a term often used in both residential and commercial buildings, making it a standard term in architectural and construction contexts.

Understanding the context, "vanity" refers to a combination of a sink and the surrounding cabinetry or counter space, and while it may also be associated with the sink itself, it describes the entire unit rather than the sink alone. The term "fixture" is broader and can denote any component that is attached to plumbing, including sinks, faucets, toilets, and bathtubs, but does not specifically name a bathroom sink. "Sinkhole" has no relevance in this context, as it refers to a geological feature rather than a bathroom component. Therefore, "lavatory" is the most precise term for a bathroom or washroom sink.