1. a small mountain lake or pool, especially one formed by glaciers

Examples

• The hikers discovered a crystal-clear tarn nestled between the peaks.
• Ancient glaciers carved out the tarn thousands of years ago.
• We stopped to rest beside the small tarn and eat our lunch.
• The tarn reflected the surrounding mountains like a mirror.
• Several tarns dotted the high alpine valley.
• The cold water of the tarn was fed by melting snow.