A central cohesive source of stability and security; a person or thing that is critical to a system or organisation.
A pin inserted through holes at the end of an axle or shaft, so as to secure a wheel or shaft-mounted device.
To adopt as, or serve as, a central cohesive source of stability and security.
The inner meaning or purpose.
The pith of certain plants.
Bone marrow biopsy.
The essence; the best part.
The substance inside bones which produces blood cells.
A friend, pal, buddy, mate.
A kind of vegetable like a large courgette/zucchini or squash.