Every betch has had to ask her besties to clarify what she meant by "hook up." Typically it's over mimosas at brunch and said after the waiter walks away. We all know the different variations: did you guys just hook up? vs. did you hook up? Well, Rihanna agrees that this vocab quiz is bullshit.
She was on Ellen playing "never have I ever" with George Clooney and asked Ellen to clarify what she meant by "hook up." Rihanna decided to break it down for Ellen and George:
Meeting up somewhere: this is how you indicate that you went out with someone, but you don't want to call it a date. It either leads to a booty call situation where neither of you acknowledge each other's presence before 11pm or the ultimate friendzone.
Making-out: this is the traditional sense of the term. Maybe a dance floor make out, a post-beer pong victory make out, you have your period, a whiskey dick situation etc. It implies that you will eventually have sex.
Seal the deal: this is how you probably use the term. It's a nice euphemism for when you don't want to say you had sex with someone the first night of the semester or because he complimented your new haircut.
So thanks Rihanna for bringing this complicated issue to the mainstream.