Refers specifically to one's own home or residence. Not used for 'one's own' in a general possessive sense.
He runs a small workshop at his own house.
noun-modifying (irregular)
Prenominal modifier meaning 'one's own' or 'self-'. Common in compounds like 自家製 (homemade) and 自家用 (for personal use). 'Autologous' is a medical term (e.g., 自家移植).
This jam is homemade.
I commute by private car.
自分 means 'oneself' as a general pronoun, whereas 自家 is limited to 'one's own house' or a prenominal 'self-' in compounds like 自家製.
実家 refers specifically to one's parents' or family home, while 自家 refers to one's own current residence, so the two are easily mixed up in meaning.
じか is written with the same kanji 直 but is a different reading meaning 'direct/without an intermediary' in everyday contexts, distinct from 直 read じき, which leans toward 'soon' or fixed relational compounds.
homemade · made in-house; housemade; made on the premises
for private use; for personal use; for home use
autointoxication; autotoxemia · cyclic vomiting syndrome
self-insurance
self-pollination
self-fertilization; autogamy
self-contradiction
self-centeredness; selfishness; egoism
home gardening; home growing
Compound of 自 (self) and 家 (house). The prenominal use developed from the idea of 'one's own household' extending to 'one's own' in general.
in-house roasting; shop roasting; home roasting
autogamy; self-fertilization
private power generation; in-house electricity generation