adherend

From adhere + -end.

adherend (plural adherends)

1. That which adheres to something else by adhesion.
   • 2017, Rhys Jones, A.A. Baker, Neil Matthews, Aircraft Sustainment and Repair, page 284:

     The aerospace industry routinely uses the tendency of clean water to 'bead' or 'break' as an indication of the presence of hydrophobic contaminant on an adherend during surface preparation.

• deharden, hardened