My apologies for such a basic question--I am a musician, not a physicist. But I cannot anywhere find the word, if one exists, that describes that elegant pause of an object such as a ball, thrown straight up, as it reaches the apex of its trajectory's power and before it obeys the power of gravity commanding it to earth.
I don't think there is a word apart from "apex" or its various synonyms. For orbiting bodies we use the prefix "ap" e.g. aphelion is the point an object orbiting the sun is furthest away, or apastron is the equivalent for a star. A object thrown up is in principle orbiting the Earth (OK, it's a highly elliptical orbit :-) so I suppose the apex of its flight would be the apogee.