seconder noun4 •The person who makes a second to a motion in any formal procedure, such as a parliamentary procedure.He's been the seconder on many motions, but I don't think he's ever made a motion himself. •A person who seconds; a person who climbs after the leader •[in compounds] Something that lasts or takes a specified number of seconds. •A Cub Scout serving as a second-in-command to a sixer. formsseconders