senescence

Merriam-Webster's Word of the Day for January 3, 2026 is: senescence \sih-NESS-unss\ noun Senescence is a formal and technical word that refers to the state of being old or the process of becoming old. // Our grandparents, now in their senescence, are enjoying spending more time with family and going on new adventures together. [See the entry >](https://www.merriam-webster.com/dictionary/senescence) Examples: “[Pilates](https://www.merriam-webster.com/dictionary/Pilates) provides improvements in core strength, flexibility and balance, even when done just once a week. It can help with stress relief, as well as anxiety and depression. Among those 60 years of age and older, Pilates has even been shown to slow the process of senescence.” — Leah Asmelash, CNN, 7 Sept. 2025 Did you know? Senescence can be traced back to Latin senex, meaning “old.” Can you guess which other English words come from senex? [Senile](https://www.merriam-webster.com/dictionary/senile) might (correctly) come to mind, as well as [senior](https://www.merriam-webster.com/dictionary/senior). But another one might surprise you: [senate](https://www.merriam-webster.com/dictionary/senate). This word for a legislative assembly dates back to ancient Rome, where the Senatus was originally a council of elders composed of the heads of patrician families. There's also the much rarer [senectitude](https://www.merriam-webster.com/dictionary/senectitude), which, like senescence, refers to the state of being old (specifically, to the final stage of the normal life span).