Definition of "adhesion"

adhesion

/ˌædˈhiː.ʒən/

noun
usually uncountable, plural adhesions
1. The ability of a substance to stick to an unlike substance.
2. Persistent attachment or loyalty.
  Quotations
  Who doubts that the fineing, whipping, torturing, hanging, embowelling of men, women, and children, guilty of no other crime than adhesion to the Catholic faith, had assisted the Pope and Philip, and their band of English, Scotch, and Irish conspirators, to shake Elizabeth's throne and endanger her life?
  1867, John Lothrop Motley, Project Gutenberg History of The Netherlands, 1555-1623, Complete‎
3. An agreement to adhere.
  Quotations
  Mistress Affery, heartily glad to effect the proposed compromise, gave in her willing adhesion to it.
  1855 December – 1857 June, Charles Dickens, Little Dorrit, London: Bradbury and Evans, […], published 1857
4. (medicine) An abnormal union of surface by the formation of new tissue resulting from an inflammatory process.
5. (biochemistry) The binding of a cell to a surface or substrate.
6. The frictional grip on a surface, of wheels, shoes etc.
  Quotations
  Several types of diesel locomotive have been tested on this working and as a result the probable choice will be Type 2 diesels in pairs, without bankers. The crucial factor in the selection of this method is the higher degree of adhesion obtained than with a single Type 4; on trial one of the latter showed that in very adverse conditions it might slip to a standstill at one of the two tricky spots on the steep climb from Tyne Dock to Consett.
  1964 September, “News: Fewer diesels for NER in 1965”, in Modern Railways, page 201