expression, noun
one's final abode; last home
A somewhat literary or solemn expression for the place where one will spend one's final years or die. Often used in contexts of retirement, old age, or terminal illness.
彼は静かな田舎に終の棲家を構えた。
He made his final home in the quiet countryside.
この小さな家が私の終の棲家になるだろう。
This little house will probably be my last abode.
From 終 (つい, 'end, final') + の (possessive particle) + すみか (棲家/住処, 'dwelling, abode'). The reading つい is an older form of 終わり (おわり). The phrase is idiomatic and literary.