tube inserted into a body cavity (as during surgery) to remove unwanted material
"The surgeon carefully inserted a drain into the abdominal cavity to remove excess fluid after the operation."
a pipe through which liquid is carried away
"The old sink had a clogged drain that refused to let any water go down."
a gradual depletion of energy or resources
"a drain on resources"
"a drain of young talent by emigration"
A conduit allowing liquid to flow out of an otherwise contained volume; a plughole (UK)
"The old sink had a clogged drain that backed up water whenever someone ran the dishwasher."
In plain English: A drain is an opening that lets water flow out of a sink, bathtub, or other container.
"The leak caused water to pool until the bucket became too heavy to lift because he used it as his only drain for the flooded basement."
Usage: Use this word to refer specifically to the physical opening or pipe that allows water to escape, such as in a sink or bathtub. It is often confused with "drain" as a verb, but here it strictly denotes the object itself rather than an action.
To lose liquid.
"The sink began to drain after I turned off the faucet."
A surname.
"The Drain family has lived in that village for over a century."
The word drain comes from the Middle English dreinen and ultimately traces back to Proto-Germanic roots meaning "to strain" or "sieve." Its original sense of filtering liquids is closely related to words for drying up, reflecting a shared history with modern terms like dry.