'Frictional' definitions:

Definition of 'frictional'

From: WordNet
adjective
Pertaining to or worked or produced by friction; "frictional electricity"; "frictional heat"; "frictional gearing"

Definition of 'Frictional'

From: GCIDE
  • Frictional \Fric"tion*al\, a. Relating to friction; moved by friction; produced by friction; as, frictional electricity. [1913 Webster]
  • Frictional gearing, wheels which transmit motion by surface friction instead of teeth. The faces are sometimes made more or less V-shaped to increase or decrease friction, as required. [1913 Webster]