If you’re like most people, you probably use the terms “chinup” and “pullup” interchangeably to mean the same hard AF upper-body exercise. But it turns out, they’re actually not synonyms. (Yeah. Mind = blown.)
How you hang onto the bar is also different. Pullups generally involve a hold that's slightly wider than shoulder-width, Sklar says. While “chinups are typically performed with a narrower grip, approximately shoulder-width,” says Sklar.