To be suitable for.

“It fits the purpose.”

To conform to in size and shape.

“If I lose a few kilos, the gorgeous wedding dress might fit me.”

To be of the right size and shape

“I wanted to borrow my little sister's jeans, but they didn't fit.”

To suffer a fit.

A small part, especially a standardized or detachable part of a device or machine.

A tube connector; a standardized connecting part of a piping system to attach sections of pipe together, such as a coupling

The act of trying on clothes to inspect or adjust the fit.

Ready, appropriate, suitable, or in keeping