cochair

co- +‎ chair

cochair (plural cochairs)

1. Someone who serves as the chair of a meeting or organization together with one or more other chairs.
   • 1988 February 19, Ben Joravsky, “A referendum gorws in the 47th Ward: boosting the current against Com Ed rate hikes”, in Chicago Reader‎:

     "On the referendum, people are asked to vote yes or no," says Hoyt, who is cochair of the Coalition for Lower Electric Rates […] .

• cochairman
• cochairperson
• cochairwoman

• cochairmanship

cochair (third-person singular simple present cochairs, present participle cochairing, simple past and past participle cochaired)

1. (transitive) To chair (a meeting) jointly.