Good question! The short answer is, the Ancient Greeks didn't have quite the same distinction we now have between "brass" and "bronze". There were several words for copper alloys, but most contained some tin, some zinc, and some other things as well. This rule still seems to hold in Modern Greek, according to the Wikipedia page you linked, with the different words being used based on color instead of composition:
Crateroma is often confused with oreichalcos, which is fundamentally an alloy of copper and zinc. This confusion, coming from the indiscriminate use of the word "mproutzos" to refer to both crateroma and oreichalcos, doesn't only exist in Greek: in English, for example, crateroma is called "bronze", and oreichalcos is called "brass". This is because, in practice, the distinctions are made based on color: in the language of commerce, "mproutzos" and "crateroma" are used for the copper alloys with the brownest colors, while the alloys with the most golden colors are called "oreichalcos".
(This is my translation, and may have errors in it, because I'm not very good at Modern Greek; an actual Modern Greek-speaker should feel free to correct it!)
First, for the most famous alloy in all of history:
Ὀρείχαλκος literally means "mountain copper", and authors disagree on what exactly it is or was. Plato suggests that it was mined directly in Atlantis and was almost as valuable as gold, while other authors say it was an especially shiny copper alloy; it's not clear what this alloy was, although some authors have different ideas.
When the Romans heard the term, they interpreted it as aurichalcum instead of orichalcum—that is, "gold copper" instead of "mountain copper"—and they applied the word specifically to gold-colored copper alloys, including zinc brass, but also copper-gold alloys used for coins.
In English and other languages, nowadays, you most often find "orichalcum" in the same places you find "Atlantis" (i.e. fantasy literature and games). The ancient authors seem to agree that true orichalcum no longer exists: it was used long ago and is now gone.
For example, here's Pseudo-Aristotle, explaining the origin of its shininess:
Φασὶ τὸν Μοσσύνοικον χαλκὸν λαμπρότατον καὶ λευκότατον εἶναι, οὐ παραμιγνυμένου αὐτῷ κασσιτέρου, ἀλλὰ γῆς τινὸς αὐτοῦ γινομένης καὶ συνεψομένης αὐτῷ. λέγουσι δὲ τὸν εὑρόντα τὴν κρᾶσιν μηδένα διδάξαι· διὸ τὰ προγεγονότα ἐν τοῖς τόποις χαλκώματα διάφορα, τὰ δ᾿ ἐπιγιγνόμενα οὐκέτι.
They say that this Mossynoecian copper is the most brilliantly shiny and purest white of all, not because it's mixed with tin, but because it's smelted and alloyed with some sort of earth. They say that the inventor of this mixture didn't teach it to anyone, so the copper products that were made there long ago are special, but the modern ones aren't any more.
(Regarding Marvelous Things Heard 62, translation mine)
Apart from oreichalcos, though, most of the words for copper alloys were more specialized. For example, craterōma was a particularly strong alloy (it comes from the word for "strength", while pyrōpos was a particularly red one (the name means "fire-eyed"). These could even be considered marketing terms, by modern standards!
But most of all, the word used for bronze was simply χαλκός—that is, "copper". The distinction between copper and bronze simply wasn't a very useful one to make in everyday conversation: if you were making weapons out of it, for example, there would obviously have to be some tin mixed in, while if you were making a mirror, there wouldn't. About 90% of the references to bronze simply call it "copper" like this.
