noun
new home; new residence
Refers to the home someone has newly moved into, newly built, bought, or otherwise started living in. Common with verbs such as 引っ越す, 移る, 構える, and 招く.
来月、新居に引っ越します。
We are moving into our new home next month.
友人を新居に招いた。
I invited my friends to my new home.
Means one's own home; it does not imply that the home is new.
A Sino-Japanese compound of 新 meaning 'new' and 居 meaning 'residence' or 'dwelling'; the spelling transparently matches the modern meaning.