Someone who serves as the chair of a meeting or organization together with one or more other chairs(noun)
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Use "cochair" in a sentence
"We had John Tower, the committee cochair, who ultimately earned considerable prestige by making this committee work."
"As President Clinton's Treasury secretary, Rubin, the former cochair of Goldman Sachs, led the fight to free the financial markets from regulation and then went on to a $15-million-a-year job with Citigroup, the company that had most energetically lobbied for that deregulation."
"“The incredible enthusiasm in this community is amazing,” said Pete Pomeroy, cochair of the Friends of Milton Hospital."