abscission
noun
ab·scis·sion ab-ˈsi-zhən 
1
: the act or process of cutting off : removal
2
: the natural separation of flowers, fruit, or leaves from plants at a special separation layer
Example Sentences
Recent Examples on the Web It’s a process called abscission, Tauscher said, where the trees retrench those chemicals and release the leaf. 
Sarah Bowman, The Indianapolis Star, 5 Oct. 2021 Day length triggers the trees to lay down an abscission layer, which in turn shuts down the chlorophyll generation. John Meyer, The Know, 24 Sep. 2019 Eventually, as the veins in the leaf close down, a layer of cells called the abscission layer forms at the base of the leaf stem before falling off. Andrew J. Tobias, cleveland.com, 3 Nov. 2017
Sarah Bowman, The Indianapolis Star, 5 Oct. 2021 Day length triggers the trees to lay down an abscission layer, which in turn shuts down the chlorophyll generation. John Meyer, The Know, 24 Sep. 2019 Eventually, as the veins in the leaf close down, a layer of cells called the abscission layer forms at the base of the leaf stem before falling off. Andrew J. Tobias, cleveland.com, 3 Nov. 2017 Word History
Etymology
Middle English abscisioun, borrowed from Medieval Latin abscīsiōn-, abscīsiō "cutting off, felling, amputation," going back to Latin, "aposiopesis," from abscīdere "to cut off or away, remove" + -tiōn-, -tiō, suffix of action nouns; spelling abscission (in Late and Medieval Latin as abscissiōn-, abscissiō) by construing the noun as a derivative of Latin abscindere "to tear off or away" — more at abscise, abscissa
First Known Use
15th century, in the meaning defined at sense 1
Medical Definition
abscission
noun
ab·scis·sion ab-ˈsizh-ən
: the act or process of cutting off : ablation