#1 prolongation n. [protraction, perpetuation, lengthening] the act of prolonging something; "there was an indefinite prolongation of the peace talks". wn #2 prolongation n. [extension, lengthiness] amount or degree or range to which something extends; "the wire has an extension of 50 feet". wn #3 prolongation n. [lengthiness, continuation, protraction] the consequence of being lengthened in duration. wn