noun
extremity
ik-STREM-uh-tee/ɪkˈstreməti/
The furthest end or limit of something.
The fingertips form the furthest extremity of the outstretched arm.

Etymology
Extremus means outermost, and extremity preserves this spatial sense as the farthest point or end. Hands and feet are called extremities because they are the body's outermost parts.
In context
the helmet should be so placed that its lower extremity reaches somewhat over the edge of the shield
More examples
- Metal caps protect the extremities of each wooden pole.
- The map marks the western extremity of our property.
- A crack runs from one extremity of the beam to the other.
Forms
extremity · extremities
extreme adjective — Farthest from the center or starting point.