IPA: /ˌʌnˈdʒʊlətəri/
KK: /ʌnˈdʒuːləˌtɔri/
Relating to or resembling waves; having a wavy form or motion.
The undulatory motion of the ocean waves was mesmerizing to watch.
Undulatory → It is formed from "undulatus" (from Latin, meaning wave-like) and the suffix "-ory" (meaning relating to or characterized by). The word "undulatory" describes something that is characterized by waves or oscillations.
Think of 'wave-like' ('undulatus') to remember that 'undulatory' refers to something that has a wave-like motion.