Step, or leap?

You can hear that a note moved and which way. This is the next question, and it is deliberately a rough one: did it move to the note next door, or did it jump past something?

That distinction is worth more at this stage than any interval name. Melodies are mostly steps with a few leaps, and the leaps are where the shape is — hearing them is how you follow a tune you have never heard.

Naming a leap exactly — a third, a fifth — comes later, and it needs this first. There is nothing to hang “major third” on until you can hear that something was skipped.