noun / verb / adjective
ski
SKEE/skiː/
A long, narrow runner worn for gliding over snow, or moving on such runners.
The long ski has an upturned tip and a boot secured in its binding.

Etymology
Norwegian ski is related to Old Norse skið, meaning literally “stick of wood.” That connection links the snow runner to the wooden board or slat fastened to the foot.
In context
when the ski flexes the heel piece can move accommodating that Flex so the boot doesn't pop out
More examples
- We ski together whenever fresh snow covers the trails.
- He skied down the gentle hill without falling.
- The ski instructor helps beginners practice their turns.
- Their skis leave parallel tracks in the fresh snow.
Forms
ski · skis · skied · skiing
skier noun — Someone who glides over snow on skis.