A checkmate, Either of a pair of plants, fungi, or other organisms that engage in sexual reproduction or conjugation with each other, A ship's officer whose duty it is to oversee the execution of the orders of the master or commander, or of his immediate superior, transitive verb_ To checkmate, To join together; to fit together; to connect; to link, To match one's self against; to oppose as equal; to compete with, intransitive verb_ To be or become a mate or mates, especially in sexual companionship, To cause (organisms) to breed or bring (organisms) into close proximity for breeding