together, as one: people or things joined in the same place, the same action, or the same fate.
At its core this word says that what is being described is not separate but joined: two or more people or things held together in company, in a shared action, or in a shared outcome. It is the word behind "both of them went together" and "can two walk together?"
From that one idea it spreads in a few natural directions. It can stress companionship, several parties doing one thing side by side. It can stress totality, sweeping everyone in without exception, so that "together" tips over into "all alike" or "every last one." And a small number of times it stands on its own as a thing rather than a description, naming the union or community that results when people are gathered as one.
These are not separate words but shades of a single picture. Whether the focus falls on being side by side, on no one being left out, or on the bond itself, the underlying claim is always the same: this is oneness, not separateness.
The lengthened form (often written "together" with an added ending) and the shorter form carry the same meaning; the difference is one of style and period, not of sense.