DictionarymasticSealing paste
noun

mastic

A paste used to seal gaps or bond building materials.

She presses each tile into the mastic on the wall.

Etymology

The original mastic was a plant resin used for chewing and other purposes. Its adhesive and sealing properties gave its name to later construction compounds with similar uses.

More examples

  • Apply mastic around the vent to seal the gap.
  • The contractor spreads mastic with a notched trowel.
  • Check whether this mastic is suitable for wet areas.

Forms

mastic · mastics

Similar words

caulk
Usually fills joints and gaps rather than bonding broad surfaces.
sealant
Emphasizes blocking air or water rather than bonding materials.
adhesive
Bonds surfaces together but need not be a paste.