convection

Concise Oxford English Dictionary © 2008 Oxford University Press:
convection/kənˈvekʃn/

▶noun transference of mass or heat within a fluid caused by the tendency of warmer and less dense material to rise.

– derivatives
convect verb,
convectional adjective,
convective adjective.

– origin C19: from late L. convectio(n-), from L. convehere, from con- ‘together’ + vehere ‘carry’.