1920, in the meaning defined at sense 1
mean square
mean square deviation
means test
“Mean square deviation.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/mean%20square%20deviation. Accessed 30 Dec. 2024.
Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!
See Definitions and Examples »
Get Word of the Day daily email!
Share