Meaning of zài jiā:
在家
to be at home; (at a workplace) to be in (as opposed to being away on official business 出差[chu1chai1]); (Buddhism etc) to remain a layman (as opposed to becoming a monk or a nun 出家[chu1jia1])
Jīntiān wǒ xiǎng zài jiā xiūxí.
今天我想在家休息。
Today I want to rest at home.
Jīntiān wǒ huì zài jiā gōngzuò, bù qù gōngsī.
今天我会在家工作,不去公司。
Today I will work at home and not go to the office.
Suīrán tā xiūxíng duōnián, dàn tā juédìng jìxù zài jiā.
虽然他修行多年,但他决定继续在家。
Although he has practiced for many years, he decided to remain a layman.