mutual aid
/ˌmjuːtʃʊəl ˈeɪd/ /ˌmjuːtʃ(ʊ)l ˈeɪd/ /ˌmjuːtjʊəl ˈeɪd/noun
Support or assistance given and reciprocated (in later use especially as a social or political mechanism); particular reciprocal agreements in international affairs, civil administration, etc.
Origin
Mid 16th century; earliest use found in Thomas Cromwell (d. 1540), royal minister. From mutual + aid.