This is the 769th most frequent Portuguese word.
lucas
A slang term in Brazilian Portuguese meaning "money" or "bucks."
The word 'Lucas' here is used as a proper noun, representing a person's name.
Lucas é meu amigo de infância.
Lucas is my childhood friend.
In this context, 'lucas' is a colloquial term used in Brazilian Portuguese to mean 'bucks' or units of currency in an informal way.
Ele comprou um carro novo por cinquenta mil lucas.
He bought a new car for fifty thousand bucks.
Again, 'Lucas' is a proper noun referring to the name of a person, serving as the subject of the action in this sentence.