place mat vs table linen

place mat and table linen both are nouns.

Word	Noun	Adjective	Verb	Adverb
place mat	Yes	No	No	No
table linen	Yes	No	No	No

As nouns, table linen is a hypernym of place mat; that is, table linen is a word with a broader meaning than place mat:

Other hypernyms of place mat include mat, napery.

place mat (noun)	table linen (noun)
a mat serving as table linen for an individual place setting	linens for the dining table