tendon, tenon

Tendon or tendon means a cord of tissue that connects a muscle to a bone--
A tendon is one of the parts of the human body.
She strained a tendon and was on crutches for months.
Tendon may also mean a strand used to reinforce concrete--
This piece of concrete has a tendon running through it; it will be tough to dig up.

Tenon or tenon means a projection on the end of a piece of wood, used to join it to another piece of wood with a mortise, like a tab in a slot--
Each piece of wood is joined with a mortise and tenon; it's very sturdy.
An Amish barn may use mortise and tenon construction.

Now that you know that, you can say--
"He climbed the ladder to check on a mortise and tenon joint, then he slipped and tore a tendon in his shoulder--the same joint he had injured before."