jamjamjamsjammedjamming2verb (jams, jamming, jammed)1to push something into a place where there is not much space: She jammed all her clothes into a suitcase.2to fix something or to become fixed so that you cannot move it: I can't open the window. It's jammed.jamjamjams1noun1(no plural) sweet food made from fruit and sugar. You eat jam on bread: a jar of strawberry jam2(pluraljams) a situation in which you cannot move because there are too many people or vehicles