senescence

se•nes•cence \si-ˈne-s^ən(t)s\   n

Definition
1.  the process of growing old, especially the condition resulting from the transitions and accumulations of the deleterious aging processes.
2. the growth phase in a plant or plant part (as a leaf) from full maturity to death
senescent adjective

Related
Senior, senile and senate all share the Latin root senex

Examples

• The processes induced by photoperiodism are called "senescence", which is a term for the collective process that lead to the aging and death of a plant or plant part, like a leaf. Senescence is a part of the larger process by which a plant goes into dormancy. There is more involved than the gradual reduction of growth.

• In general terms, leaf senescence is a way for a deciduous plant to prepare for winter and recycle some of the valuable and often scarce mineral nutrients, such as nitrogen and phosphorus. Leaf senescence is also a way to to get rid of old and photosynthetically less efficient leaves in both deciduous and evergreen plants.

Origin

senescent, from Latin senescent-, senescens, present participle of senescere to grow old, from sen-, senex old

First Known Use: 1695

Sources: Merriam-Webster, MW Medical,

Why This Word:

Happy Autumnal Equinox (at 11:09 this evening)!

With the leaves just starting to turning, the nights getting cooler and my own birthday soon upon me, I suppose it only natural to think about senescence. But it's a word so seldom used that one ubiquitously hears it referred to instead as the aging process. When a word can stand in for a phrase, that's a sure sign that it has added to our power of expression.

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