above all; more than anything; first and foremost
Adverbial use emphasizing that something is the most important thing or the top priority.
Health is more important than anything.
Above all, please ensure safety first.
expression, noun which may take the genitive case particle 'no', noun
Noun/adjectival use describing something as the best or most desirable thing. Often used with の or as a predicate.
My family's smiles are the greatest happiness.
This result is the best possible.