noun
each house; every house; door to door
Refers to every individual house or household, often in contexts like visiting, delivering, or checking each one.
新聞配達は戸々に新聞を届ける。
The newspaper delivery person delivers newspapers to every house.
調査員が戸々を回ってアンケートを取った。
The surveyors went door to door collecting questionnaires.
家家 (いえいえ) also means 'each house' or 'every house', but is more colloquial and uses the native Japanese reading. 戸々 (ここ) is slightly more formal and uses the Sino-Japanese reading.
Reduplication of 戸 (こ, 'house') with the Sino-Japanese reading, forming a distributive expression meaning 'each house'.