To pervade means to spread throughout every part of something, like a smell filling every room of a house or an attitude affecting everyone in a group. When something pervades, it reaches everywhere, becoming present in the whole space or situation.

Think about how the smell of fresh cookies pervades a kitchen, drifting into the hallway, the living room, and even upstairs. Or how excitement pervades a school on the last day before winter break, with every classroom buzzing with the same energy. When sadness pervades a story, it colors every scene and chapter, not just one moment.

The word often describes things you can't see but definitely feel: moods, attitudes, ideas, or influences. A spirit of teamwork might pervade a successful sports team, affecting how players practice, communicate, and support each other. Tension can pervade a room where people are arguing. Music from a parade can pervade the streets of a neighborhood.

Something that pervades is pervasive. If a bad habit becomes pervasive in a classroom, it means it has spread beyond one or two students to become a widespread problem affecting the whole group.