Senescence is the process of becoming old and beginning to show the wear of age. Biologists use it for living things: a cell that has stopped dividing, a leaf that is dying on the tree, a body whose systems are slowing.

Senescence衰老是the process of becoming old and beginning to show the wear of age是變老、開始顯出歲月痕跡的過程。Biologists生物學家use it for living things用這個字來說有生命的東西：a cell that has stopped dividing一個停止分裂的細胞、a leaf that is dying on the tree一片在樹上枯萎的葉子、a body whose systems are slowing一個各系統逐漸變慢的身體。

It is a cool, technical noun, the name of a process, not a rude word for a person. You will meet it in science, medicine, and careful writing about ageing.

It is它是a cool, technical noun一個冷靜、專業的名詞，the name of a process是一個過程的名稱，not a rude word for a person不是拿來罵人的字。You will meet it你會在in science, medicine, and careful writing about ageing科學、醫學和嚴謹討論老化的文章裡遇到它。

Everyday English just says getting old or ageing. Though actually, scientists sometimes separate ‘getting older in years’ from senescence, the decline that often comes with those years — the tidy school word ageing covers both, and this one is narrower. It is not a word to aim at someone’s face.

Everyday English日常英文just says getting old or ageing就直接說getting old或ageing。Though actually不過事實上，scientists有時候科學家sometimes separate 'getting older in years'把「歲數增加」from senescence跟senescence分開來看，the decline that often comes with those years指的是通常伴隨著年齡而來的衰退——the tidy school word ageing而學校教的ageing這個字covers both兩者都涵蓋，and this one而這個字（senescence）is narrower範圍比較窄。It is not a word to aim at someone's face這不是拿來當面說人的字。