extender

UK: /ɪkˈstɛndə/ US: (ik sten′dər)

WordReference Random House Unabridged Dictionary of American English © 2025

ex•tend•er  (ik sten′dər), n. 

1. Nutrition a substance added to another substance, as to paint or food, to increase its volume or bulk:
   to add cereal and soy protein to hamburger as extenders.
2. Photography See under converter (def. 8).

• extend + -er¹ 1605–15

Collins Concise English Dictionary © HarperCollins Publishers::

extender / ɪkˈstɛndə/ noun

1. a person or thing that extends
2. a substance, such as French chalk or china clay, added to paints to give them body and decrease their rate of settlement
3. a substance added to glues and resins to dilute them or to modify their viscosity