Contextual means “about the situation around something” — the place, the time, the people, the words before and after, the history. In a reading class, a contextual clue is a hint from the sentences around a new word. At work, a contextual factor is something in the setting that changes how you should understand an act. Though actually, people stretch this word a lot in school and offices: “That’s very contextual” can mean “it depends; you cannot judge it alone.” It is a classroom and office word more than a kitchen-table word. The noun behind it is context: everything around a thing that helps you understand it.