Definitions:
of first importance; main

of the best possible quality; excellent

(of a number) divisible only by itself and unity (e.g. 2, 3, 5, 7, 11).

the state or time of greatest vigour or success in a person's life

a service forming part of the divine office of the western church, traditionally said at the first hour of the day (i.e. 6 a.m.), but now little used.

a prime number.

a symbol (ʹ) written after a letter or symbol as a distinguishing mark or after a figure as a symbol for minutes or feet.

the first of eight parrying positions, used to protect the upper inside of the body, with the sword hand at head height in pronation and the tip of the blade pointing downwards.

a special section in a cycle race, attracting a special prize.

make (something) ready for use or action.

prepare (someone) for a situation, typically by supplying them with relevant information