排水口

1. Origins, structure, and basic meaning

• Structure: Written 排水口 and read はいすいこう, it denotes the opening through which used water or rainwater drains away.
• Basic usage: It appears as a kitchen drain collecting debris and an outdoor drain blocked by leaves.

2. Common pitfalls and similar expressions

• Opening rather than entire pipework
  • It identifies the drain mouth or outlet, not the whole plumbing system.