generality
A broad, vague statement that leaves out specific details.
A generality is a broad statement that applies to many cases but doesn't focus on specific details or exceptions. When someone speaks in generalities, they're describing what's usually true rather than what's always true or true in every particular instance.
For example, saying “kids like video games” is a generality. It's true for many children, but not for every single one. Some kids prefer reading, sports, or building things. The statement captures a general pattern without accounting for individual differences.
Teachers sometimes ask students to move beyond generalities in their writing. Instead of writing “Ancient Egypt was interesting,” they want specific details: “Ancient Egyptians developed a writing system using hieroglyphics and built massive pyramids that required decades of work and thousands of workers.” The first sentence is a generality; the second provides concrete information.
Generalities aren't necessarily wrong, but they can miss important nuances. If you say “science is hard,” you're making a generality that might discourage someone from trying. “Biology requires memorizing many terms, while physics involves solving mathematical problems” gives a more useful, specific picture.
The phrase “speaking in generalities” often suggests someone is being vague on purpose, perhaps to avoid a difficult question or to sound knowledgeable without actually saying much.