What bicycle parts are held by the bottom bracket?

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An African American family of four, all wearing helmets, rides bicycles together on a tree-lined country trail, with two children in front and two adults following behind. — bicycle Family bicycling on a country road.

The term "bottom bracket" refers to the assembly on a bicycle that connects the crankset to the frame and allows the cranks to rotate freely.

The bottom bracket holds the following components:

Bearings: These allow the spindle to rotate smoothly within the frame shell.
Spindle (or Axle): This component passes through the bottom bracket shell and connects to the crank arms.
Cups or Cartridge: These house the bearings and secure the assembly into the bicycle's bottom bracket shell.

By housing these parts, the bottom bracket serves as the central pivot point for the drivetrain, enabling the rider to transfer power from the pedals to the chain and wheels.1