"Macaco" is a word used for an animal (a monkey) and a mechanical device you use to lift heavy loads (a jack).
Isto é um macaco:
Mas isto também é um macaco:
So EVERY monkey is "macaco"? In my mother language, we have word "makak", what is only one species of monkey, so I am a little bit confused...
Yes, all monkeys are "macacos" (technically the term should apply to macaques only, but it's pretty widespread in reference to all non-human simians). Other words exist for different types of members of the genus Macaca and/or other primates, and if the animal is well known that is probably the term people will use to refer to it (chimpanzé - chimpanzee; babuíno - baboon; gorila - gorilla; lémur - lemur; orangutango - orangutan, etc.).