linchpin /linchˈ or linshˈpin/

1. A pin used to keep a wheel on its axle
2. A person or thing essential to a plan, organization, etc (figurative)

• electricians
• electricities
• electricity
• electric motor
• electric motors
• electric organ
• electric organs
• electric piano
• electric pianos
• electric radiator
• electric radiators
• electric ray
• electric rays
• electrics
• electric seal
• electric seals
• electric shock
• electric shocks
• electric storm
• electric storms
• electrifiable
• electrification
• electrified
• electrifier
• electrifiers