keystones
Central locking wedges
Keystones are the wedge-shaped stones at the top of arches, locking the other stones in place.
Because removing the keystone causes the arch to collapse, the word extends to anything essential that holds a system together: Agriculture and mining are the keystones of the state's economy.
A keystone species is one whose presence maintains an ecosystem's structure.
Curved spanning structure
- masonryBuilding with mortared blocks
- vaultSecure storage chamber
- bridgeStructure spanning an obstacle
- wedgeTapered splitting tool
crown · abutment · springer · Roman · lintel · span · load-bearing · compression
Upright architectural support
- foundationUnderlying support structure
- bedrockSolid stone underground
- linchpinVital securing element
- cruxMost important point
basis · core · essential · fundamental · anchor · underpinning · mainstay · backbone
Finest taxonomic rank
- ecosystemInterconnected organisms and surroundings
- biodiversityRange of life forms
- apexUppermost point or culmination
- predatorOrganism that consumes others
wolves · otters · bees · coral · trophic · cascade · food web · conservation
Northeastern founding colony state
- stateCondition or mode
- HarrisburgPennsylvania state capital
- PhiladelphiaPennsylvania's largest metropolis
- PittsburghWestern Pennsylvania industrial city
Quaker · symbol · motto · colonial · American · flag · emblem · nickname
arch
Curved spanning structure
wedge · crown · abutment · springer · Roman · lintel · span · load-bearing · compression · centering
pillar
Upright architectural support
- foundationUnderlying support structure
- bedrockSolid stone underground
- linchpinVital securing element
crux · basis · core · essential · fundamental · anchor · underpinning · mainstay · backbone · centerpiece
species
Finest taxonomic rank
- ecosystemInterconnected organisms and surroundings
- biodiversityRange of life forms
- apexUppermost point or culmination
predator · wolves · otters · bees · coral · trophic · cascade · food web · conservation · extinction
Pennsylvania
Northeastern founding colony state
- stateCondition or mode
- HarrisburgPennsylvania state capital
- PhiladelphiaPennsylvania's largest metropolis
Pittsburgh · Quaker · symbol · motto · colonial · American · flag · emblem · nickname · commonwealth
- building partsfacades, wall, door, windows, floor
- masonrymason, brick, bricks, mortar, cement
- ancient engineeringarches, aqueducts, bridges, masonry, foundations
- classical architectureIonic order, Corinthian order, Doric column, Corinthian column, Ionic
- exterior trimfascia, soffit, cornice, bargeboard, crown molding
- LEGO DimensionsBatman, Gandalf, portal, fun packs, minifigures
keystonesdecorative trim
Non-functional aesthetic border
embellishments · decorative moldings · veneers · finishing touches · cladding
keystonestrivialities
Insignificant matters
peripherals · incidentals · afterthoughts · frills · superfluities
- Keystone CopsInept cinematic policemen
- keystone speciesOutsized ecological impact organism
- Keystone KopsBungling silent-era police