prime target

: the second of the canonical hours

: the first hour of the day usually considered either as 6 a.m. or the hour of sunrise

: the earliest stage

: first in time : original

: of, relating to, or being a prime number — compare relatively prime

: having no polynomial factors other than itself and no monomial factors other than 1

: fill, load

: to prepare for firing by supplying with priming

: to insert a primer into (a cartridge case)

: a mark to shoot at

: a target marked by shots fired at it

: something or someone fired at or marked for attack

: to make a target of

: to direct or use toward a target