Appoggiaturas are non-chord tones that approach a consonant note by leap or skip, usually with an accented grace note. They create tension before resolving into the main melody note.
Related terms
Escape tones: Non-chord tones that approach a consonant note by step, then move away from it by leap in the opposite direction.
Suspension: A note that is held over from the previous chord and then resolves downward.
Passing tones: Non-chord tones that connect two consonant notes by stepwise motion.