A small round piece of linen placed under a dish or bowl WordNet 3.0 & Open English WordNet

A doily is an ornamental mat, typically made of paper or fabric, and variously used for protecting surfaces or binding flowers, in food service presentation, or as a clothing ornamentation, as well as a head covering for Jewish women and Christian women. Wikipedia

An ornamental table mat supposedly invented by a Mr Doiley Wikipedia Disambiguation

Small mat, usually of crochet-work, laid on furniture fir decoration and protection Wikidata

A small, decorative mat (made of cotton or lace) that is placed underneath objects to protect the surface. OmegaWiki

A small ornamental piece of lace or linen or paper used to protect a surface from scratches by hard objects such as vases or bowls; or to decorate a plate of food. Wiktionary

Ornamental piece. Wiktionary (translation)