marrow (

     n 1: the fatty network of connective tissue that fills the
          cavities of bones [syn: bone marrow]
     2: any of various squash plants grown for their elongated fruit
        with smooth dark green skin and whitish flesh [syn: {marrow
        squash}, vegetable marrow]
     3: very tender and very nutritious tissue from marrowbones
        [syn: bone marrow]
     4: large elongated squash with creamy to deep green skins [syn:
         vegetable marrow]
     5: the choicest or most essential or most vital part of some
        idea or experience: "the gist of the prosecutor's
        argument"; "the heart and soul of the Republican Party";
        "the nub of the story" [syn: kernel, substance, core,
         center, essence, gist, heart, heart and soul, inwardness,
         meat, nub, pith, sum, nitty-gritty]