the.com/keystone
The one stone holding the arch up by refusing to fall down.
means The central wedge-shaped stone at the top of an arch that locks all the other stones in place, and by extension the one crucial element that holds a whole system together.
from A plain English compound of 'key'—in the old sense of something that fastens or locks—and 'stone.' In masonry the topmost wedge does exactly that: it jams the two halves of an arch against each other so nothing can slip. From the literal stone the word spread outward to mean any indispensable part, the piece you dare not remove.
- wedge shape
- Locks all other stones in place under pressure
- last placed
- Set after the arch is fully built
- keystone species
- Remove it and the whole ecosystem collapses
- state nickname
- Pennsylvania, central to the original colonies
- compression king
- Heavier load makes the arch stronger, not weaker
keystone species — sea otters in kelp forests: remove them and ecosystem collapses by 90%
keystone pipeline — transcanada oil pipeline project: $8 billion, alberta to nebraska, rejected 2021
keystone cops — 1912-1917 silent film series: slapstick comedies about bumbling police