a. 1. Resembling, or in the nature of, waves; having a wavy surface; undulatory. [ 1913 Webster ]
2. (Bot.) Waved obtusely up and down, near the margin, as a leaf or corolla; wavy. [ 1913 Webster ]
3. (Zool.) Formed with elevations and depressions resembling waves; having wavelike color markings; as, an undulated shell. [ 1913 Webster ]