Screws are much used to hold together pieces of wood or to fasten something; -- called also wood screws, and screw nails.
To hold together, to be joined; not to separate; to remain in union.
Atoms by themselves would be like a heap of loose nails which need to be magnetized if they are to hold together.
The above list will hopefully provide you with a few useful examples demonstrating the appropriate usage of "hold together" in a variety of sentences. We hope that you will now be able to make sentences using this group of words.