building block

building block
    n 1: a single undivided natural thing occurring in the
         composition of something else; "units of nucleic acids"
         [syn: {unit}, {building block}]
    2: a block of material used in construction work
    

52 Moby Thesaurus words for "building block":
      air, atom, atomic particles, atoms, brute matter, chemical element,
      component, constituent, core, distillate, distillation, earth,
      element, elementary particle, elementary unit, elixir, essence,
      fabric, fire, fundamental particle, gist, heart, hyle, hypostasis,
      kernel, marrow, material, material world, materiality, matter,
      meat, medium, molecule, monad, natural world, nature, nub,
      physical world, pith, plenum, quintessence, sap, soul, spirit,
      stuff, substance, substratum, sum and substance, tangible,
      the four elements, unit of being, water