Simple past tense and past participle of matter.(verb)
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Use "mattered" in a sentence
"Perhaps he had believed that a name mattered little when the life expectancy was short."
"Rather than make a self-deprecating joke, he opted instead to make a self-inflating one, as if to say that the title mattered less than the man."
"I obsessed about the smallest detail—even telling myself that the smoothness of a word mattered; the smooth flow of letters when joined, with letters always slanting slightly to the right."