13-Letter Words Containing: I,R,R,O,S,E

• an instrument that indicates whether two periodic motions are synchronous (especially an instrument that enables a pilot to synchronize the propellers of a plane that has two or more engines)

• an antineoplastic drug used to treat Hodgkin's disease

• Any qualified majority, specified in advance of a vote, required for the vote to be passed

• the fruit of the chokecherry tree

• a common wild cherry of eastern North America having small bitter black berries favored by birds