1. The most important or central fact in a matter, case, or situation
The main fact of the case is that he was present at the scene.
O fato principal do caso é que ele estava presente no local.
2. In law or formal contexts, the primary or essential fact upon which an argument or decision is based
The judge focused on the main fact rather than peripheral details.
O juiz focou no fato principal em vez de detalhes periféricos.