Not really, technically a harem will require all girls to be gunning for one guy, but also that guy to be interested in all girls... what we usually get is a guy that runs away from every girl that gets serious with him... but like the misuse of fanservice for ecchi, we tend to misuse harem too.
You're full of surprises! Yozora first? Rika/Sena makes sense, but not that sour spineless tsundere (who nonetheless had the best butt/thighs in the show). For me none could ever beat Kobato, she reminded so much of my cat