Third-person singular simple present indicative form of alternate.(verb)
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Use "alternates" in a sentence
"You know that ‘The plaque for alternates is down in the ladies room’ right?"
"It took the attorneys about 45 minutes to pick the 12 jurors and four alternates from a pool of 40 prospective panelists."
"On Friday, the defense and prosecution will each get a chance to remove as many as 12 jurors as a panel of 12 jurors and four alternates is chosen to hear the case."