polyfill

Short definition from Wiktionary

Noun

1. 1
   A synthetic textile used for bulk or insulation, e.g., in stuffed animals or coats.
2. 2
   An algorithm to fill a polygon with a particular color.
3. 3
   A plugin that provides the functionality of newer browsers to older versions.

Verb

1. 1
   To create or apply a polyfill.