* σύνθεσις (synthesis): This is probably the closest single word and refers to the combination of different parts or elements into a whole, often in a complex or intellectual way.
* συναρμογή (synarmoge): This implies fitting parts together, often mechanically or in a structured way. Think assembling something.
* σύνδεσμος (syndemos): This means "bond" or "link," so it's appropriate if "putting together" implies connecting things.
* συγκρότηση (sygkrotisi): This means "composition" or "constitution" and refers to the act of forming or establishing something by combining elements.
To choose the best word, you need to consider *what* is being put together and *how*.