Definition of undulate

The word "undulate" shares its origin with the concept of ocean waves, which are known to undulate, or move in a wavelike motion. The word itself comes from the Latin verb "undulāre," which means "to make ripple marks," or "to wave." In Latin, "undulāre" is a combination of the prefix "un-," meaning "one," and "dulāre," meaning "to soften or soothe," which is rooted in the Proto-Indo-European word for "to melt." In Latin, "dulāre" specifically referred to the idea of waving or relaxing, as in the movement of water. The Latin "undulāre" entered the English language via the Old French word "onduler," which means "to wave." The French verb eventually became "ondoyer," then "onduire," and finally "onduler." The English word "undulate" likely derived from the Middle French "onduler," although it is also possible that it came directly from the Latin verb. In any case, the English word "undulate" entered the language by the mid-1500s, and its original meaning of "waving" or "rolling" remains largely intact today. The use of "undulate" to describe the wavelike motion of ocean waves is particularly appropriate, given its etymology, but the word is also widely used to describe wavelike motions in other contexts, such as the movement of plants' leaves or the pattern of a wave moving across a fabric.