- Absolutely necessary
- Crucial
- Fundamental
- Inherent
- Linchpin
- Must-have
- Necessary
- Chief support
- Linchpin
- Pillar
- Principal to remain chief support
- The stay extending from the foot of the foremast to the
maintop.
- Main support; principal dependence.
- Access code
- As neat as a ...
- Cook’s utensil, rolling ...
- digital location coordinates
- Fasten
- Fastening device
- Narrow brooch