Homonym: tube (Container)
A "tube" is a hollow cylindrical object, often made of materials like plastic, metal, or glass. Tubes can vary in size and are commonly used in various applications, such as packaging, construction, and transportation. For example, a toothpaste tube is designed to dispense a small amount of paste when squeezed.
In transportation, a tube can refer to an underground railway system, such as the London Underground, often called "the Tube." This system consists of trains that run through tunnels beneath a city, providing an efficient way for people to travel. The Tube is an essential part of urban infrastructure in many cities worldwide.