Can someone properly define a jump attack in this game?

So recently my boyfriend has started playing Elden Ring, and I've been watching him play (mind you, I've done a few playthroughs of my own so far). He's been doing pretty well so far, but at one point he says, "I thought you said jump attacks were good." He does one, and I tell him it's a skill you have to get used to, but then he proceeds to say that whatever he just did (using the Uchigatana) wasn't a jump attack. This leads to a debate between us as to what a jump attack is. He claims it's supposed to be a special animation, not a normal attack midair, and I say that by button inputs he's still doing the general terminology of a jump attack.

I main the Starscourge Greatswords, with the Claw Talisman on, and I do jump attacks all the time. I can see the difference in the damage. He's claiming that weapon might have a proper jump attack, but the weapon he used then and his current one (Bloodhound's Fang), doesn't have one. I define a jump attack as pressing jump+R1 (or R2), but he thinks a special animation is what defines it properly.

For all we know I might be oversimplifying the term, in which case I will be humbled, but by Elden Ring's standards, what IS a jump attack?