This is the 8458th most frequent Portuguese word.
vírus
A microscopic infectious agent that replicates only inside living cells.
Here, 'vírus' is a noun referring to a biological agent causing disease.
O vírus que causa a gripe se espalha rapidamente.
The virus that causes the flu spreads quickly.
In this case, 'vírus' is used metaphorically to refer to malicious software.
Computadores antigos são mais vulneráveis a vírus.
Old computers are more vulnerable to viruses.
Here, 'vírus' again denotes a biological entity, emphasizing scientific research.