The word pipe has several meanings:

1. A tube that carries liquids or gases from one place to another. Water pipes bring fresh water into your house and carry wastewater away. Oil pipelines transport fuel across hundreds of miles. Without pipes, modern cities couldn't function: no running water, no heat, no gas for cooking.
2. A small tube with a bowl at one end, traditionally used for smoking tobacco. You might see pipes in old paintings or stories, like Sherlock Holmes with his curved pipe. Today, pipes like this are less common than they once were.
3. To speak or sing in a high, thin voice. A bird pipes its morning song. When someone pipes up during a meeting, they speak suddenly, often with a somewhat high or clear voice.
4. In music, any tube that makes sound when air flows through it. Organ pipes create music in churches. A bagpipe uses several pipes together. Pan pipes are ancient instruments made from different lengths of hollow reed.