pol ‧ y ‧ es ‧ ter /ˈpɒliestə, ˌpɒliˈestə◂ $ ˈpɑːliestər/ BrE AmE noun [uncountable]
[ Date: 1900-2000 ; Origin: poly- + ester type of chemical compound (19-21 centuries) (from German essigäther 'acid ether' ) ]
an artificial material used to make cloth:
a blue polyester shirt