Best used when describing something that moves in a wave-like motion, often gracefully. The belly dancer's hips undulated to the rhythm of the music.
Pro Tip 2/3
Natural Descriptions
Effective in describing landscapes or natural elements, suggesting flowing, organic movement. The vast wheat field undulated under the caress of the wind.
Pro Tip 3/3
Visual Imagery
Use it to create a visual effect of smooth, wave-like movements in the reader's mind. The curtain undulated as a gentle breeze slipped through the open window.