Being very important, or key to something.
Having or containing the centre of something.
Being in the centre.
Exerting its action towards the peripheral organs.
centre
appropriate, suitable; believable; promising, having a good potential
probable; having a greater-than-even chance of occurring
Reasonably to be expected; apparently destined, probable
attractive; pleasant
plausible; within the realm of credibility
leading with high probability to some specified outcome
Something or somebody considered likely.
Probably.