Tranquil means peaceful and calm, without disturbance or agitation. A tranquil lake sits perfectly still on a windless morning, its surface like glass reflecting the sky. A tranquil library offers quiet space where students can read and think without chaos or noise.

The word captures a special quality of calmness. A classroom might be quiet because everyone's taking a test, but a tranquil garden is quiet in a more complete way: the air feels settled, sounds are gentle, and everything seems at rest. When someone has a tranquil expression on their face, they look peaceful and untroubled, not tense or worried.

Places can be tranquil, like a monastery or a forest clearing at dawn. Moments can be tranquil too: those few minutes before the household wakes up, or sitting by a pond watching dragonflies hover over the water. The related noun is tranquility, which is the state of being tranquil. After a hectic week of tests and activities, you might seek some tranquility by spending Saturday morning reading in your favorite chair, or taking a quiet walk where your mind can settle.