What is technically considered an attack?

[MeeposFire]

Neither does a cleric casting Sacred Flame... you're stating the cleric isn't making an attack?!?

IN terms of game mechanics no the cleric is not making an attack, even if I may describe it as such outside of a game context. Remember the game can define a term as having a different definition from how it is generally used.

Make note that this does have game implications a cleric using sacred flame does not get a bonus 1d6 damage on his hex target (assuming they had hex of course) and also the rogue he is targeting cannot use uncanny dodge to reduce the damage.