IPA: /ˌæntɪməˈkæsə/
KK: /ˌæntɪməˈkæsər/
A cover used to protect the back or arms of furniture, especially chairs and sofas, from dirt and wear.
She placed an antimacassar on the armchair to keep it clean.
Antimacassar is formed from "anti-" (meaning against) and "macassar" (from the name of a type of oil, specifically Macassar oil, which was used to style hair). The word refers to a cloth placed on furniture to protect it from the oil used in hair styling, hence it is against the effects of Macassar oil.
Think of 'against' ('anti-') the oil from Macassar — that's why an antimacassar is used to protect furniture from that oil.