IPA: /ˌdʒuːvəˈnɛsəns/
KK: /dʒuːvəˈnɛsəns/
The condition of becoming young or youthful, often referring to a period of growth or development.
The juvenescence of the plant was evident as it began to sprout new leaves.
Juvenescence is formed from "juvenis" (meaning young) and "-escence" (meaning the process of becoming). The word describes the process of becoming young or youthful.
Think of 'juvenis' meaning young, and '-escence' indicating a process — so juvenescence refers to the process of becoming young.