
The energy lost from the movement of a fluid in a conduit (pipe) due to the disturbances created by the contact of the moving fluid with the surfaces of the conduit, or the additional pressure that a pump must provide to overcome the resistance to fluid flow created by or in a conduit.
Found on
http://www.daviddarling.info/encyclopedia/F/AE_friction_head.html

The energy lost from the movement of a fluid in a conduit (pipe) due to the disturbances created by the contact of the moving fluid with the surfaces of the conduit, or the additional pressure that a pump must provide to overcome the resistance to fluid flow created by or in a conduit.
Found on
https://www.encyclo.co.uk/local/22819

(in a hydraulic system) the part of a head of water or of another liquid that represents the energy that the system dissipates through friction with the sides of conduits or channels and through heating from turbulent flow.
Found on
https://www.infoplease.com/dictionary/friction-head
No exact match found.