Questions & Answers about Errar é humano.
Here, errar means to make a mistake or to be wrong.
In other contexts, errar can also mean things like to miss a target or answer, but in Errar é humano, it means making mistakes in a general sense.
Because Portuguese, like English, can use the infinitive as the subject of a sentence.
So:
- Errar = to make mistakes / making mistakes
- é humano = is human
Literally, the structure is very close to To make mistakes is human in English.
This is a very normal construction in Portuguese.