“additionally”

Used to introduce a point that reinforces or extends what has already been said.

“The design was elegant; furthermore, it cost half what competitors charged.”

Best for: Works well in formal writing, essays, and professional reports to build an argument.

Introduces an additional fact that strengthens or goes beyond the previous statement.

“The data was conclusive; moreover, it had been independently verified three times.”

Best for: Strong in academic and journalistic writing when stacking evidence or claims.

In addition to that; attached or related to the matter already discussed.

“The contract outlined the penalties, and all amendments thereto were binding.”

Best for: Best suited to legal documents, contracts, and formal institutional writing.

In addition to everything else; used to add a final, often surprising, quality.

“She was formidable in argument and, withal, surprisingly warm in private.”

Best for: A literary archaism that adds elegance and mild surprise; ideal for essays or historical fiction.

As an added extra, often implying something unexpected or bonus-like.

“He fixed the engine and repainted the hood into the bargain.”

Best for: Conversational and punchy; great for informal writing or character voice in fiction.

In a manner that comes as a subsequent or additional development upon something prior.

“The crisis was economic, and superveningly, it became a crisis of public trust.”

Best for: Extremely rare; suits dense philosophical or legal prose where layered causation matters.