To tamp means to press or pack something down firmly and evenly. When a gardener plants seeds, she might tamp down the soil around them, pressing gently with her hands or feet to remove air pockets and help the roots take hold. When a construction worker pours concrete, he uses tools to tamp it, making sure it settles evenly without gaps or bubbles.

The word suggests careful, deliberate pressing rather than wild pounding. You're not smashing or crushing: you're compacting and smoothing. Someone making a gravel path might tamp down each layer before adding the next. A railroad worker historically used a long rod called a tamping iron to tamp material into holes drilled in rock.

You might also tamp down fears or excitement, meaning to calm or control strong feelings. When wild rumors spread through your school, a teacher might tamp down the panic by calmly explaining what really happened. This figurative use captures that same sense of pressing something unruly into a more settled, controlled state.