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)

• colostomies
• colostomy
• colostomy bag
• colostomy bags
• colostric
• colostrous
• colostrum
• colostrums
• colotomies
• colotomy
• colour
• colourable
• colourably
• colourant
• colourants
• colour a pipe
• colouration
• colourations
• colour bar
• colour bars
• colour-blind
• colour blindness
• colour code
• colour-code
• colour-coded