extensor
nounUK /ɪkˈstɛnsə/
US /ɪkˈstɛnsər/
A muscle that makes a body part straight.
The extensor muscle in his arm helped him straighten his elbow.
OTHER MEANINGS
2. A device or tool that stretches or extends something.
The extensor on the machine pulled the fabric tight.
3. A muscle that extends a limb or digit away from the body.
The extensor of the fingers lets you open your hand wide.
4. Something that increases the range or reach of an activity.
The new bridge acted as an extensor of the city's trade routes.