linchpins

axle

Shaft for wheel rotation

• fastenerSecures things together
• wheelRotating circular frame
• hubCentral connection point

spoke · cart · wagon · harness · hitch · coupling · shaft · spindle · bearing · yoke

cornerstone

Foundational building block

• keystoneArch's central locking stone
• bedrockSolid stone underground
• mainstayPrimary source of support

anchor · backbone · pillar · fulcrum · hub · centerpiece · nexus · crux · nucleus · heart

indispensable

Utterly required, irreplaceable

• vitalEssential or sustaining existence
• integralAntiderivative or crucial component
• criticalExpressing disapproval or importance

crucial · pivotal · key · central · core · fundamental · necessary · essential · paramount · primary

brace

Device providing structural stability

• buttressArchitectural wall reinforcement
• strutProud, showy gait
• propSupport or stage item

reinforcement · girder · stanchion · truss · underpinning · mount · shore · column · beam · joist

• reliablesmainstays, staples, standbys, stalwarts, dependables
• wagonmakingwheels, axle, spokes, hubs, rims
• Key Playerskey players, MVPs, all-stars, franchise players, elite players
• backbonevertebrae, vertebra, spinal column, vertebral column, spinal cord
• powerhousestitans, giants, juggernauts, heavyweights, behemoths