A link is something that connects two things together somehow.
A link is also one piece of a chain.
Lint is a collection of very short fabric fibers that have broken off clothing and linen as it is being used. Lint tends to collect inside washing machines, dryers, the inside of pockets and even in your belly button.
A lintel is a horizontal structural component, supported at each end by a post. Lintels are commonly seen above windows and doors in older houses, supporting the bricks or stone above the opening.