To scour means to clean something by scrubbing it hard and thoroughly. When you scour a dirty pot, you rub it vigorously with a brush or rough pad to remove every bit of stuck-on food. Cooks scour their pans after making sticky foods like caramel. Sailors scour the deck of a ship to keep it spotless.

The word also means to search an area thoroughly and carefully. Police might scour a forest looking for clues. You might scour your room hunting for a lost retainer, checking under the bed, behind the desk, and in every drawer. When researchers scour old documents, they read through them meticulously, searching for specific information.

Both meanings share the idea of being thorough and leaving nothing unchecked. Whether you're scouring dirt off a surface or scouring a place for something hidden, you're working hard and paying close attention to every detail.