ap ‧ o ‧ gee /ˈæpədʒiː/ BrE AmE noun [countable]
[ Date: 1500-1600 ; Language: French ; Origin: apogée , from Modern Latin apogaeum , from Greek , from apogaios 'far from the earth' , from apo- ( ⇨ ↑ apocalypse ) + ge 'earth' ]
formal the most successful part of something SYN apex :
His political career reached its apogee in the 1960s.