0 a hole in a bath, sink, etc. through which water flows away and into which you can put a plug -- （浴缸、洗滌槽等的）排水孔，滲水孔
These uncontrolled spillway devices are also called "morning glory", "plughole", "glory hole" or "bell-mouth" spillways.
That principle has gone down the plughole.
It is simply a revenue plughole.
The road race is a plughole down which ratepayers' and poll tax payers' money will be poured unless it is stopped.
In seeking to improve the quality of the bathwater we have put the baby well and truly down the plughole.
If there is no home market, these firms will go down the plughole as well.
When we finish with them, presumably they can be flushed down the lavatory or put down the plughole, it matters not.
One industry after another has gone down the plughole.
