Bunch actually is somewhat specific. However, cluster is another word used with grapes.
Funnily enough, "grape" comes from the Middle French term grappe de raisin, meaning bunch of grapes, but was shortened by English speakers to grappe (and then grape). So, English speakers are in effect almost saying, a bunch of bunches.
"O" is the Portuguese masculine definite article ("the" in English) – and also a masculine reflexive pronoun just to confuse things – but not all words that end in "o" are masculine. Almost all words that end in ção are feminine (except o coraçao = heart) so would take the feminine article ("a"). There is also a moto and a foto but those are abbreviations of longer words.
Dia, Idioma, Gorila, Cinema (generally all that end in "ema" as GScottOliver pointed out as being Greek), Policia (Policial in Brazil – there are several professions that end in "a" but have the masculine article, except when referring to a female such as Dentista). Words that end in an accented "a" are also usually masculine (maçã being an exception).
I reported the same thing on a few other languages, especially Russian and got slammed. Maybe our expectations are too high? I mean, sometimes in English, my native language, what I say and what appears on the screen are two different things. However, I'm loving the fact I am saying things in Portuguese...7 weeks in..and it appears the same...for the most part..on the screen. So, it is overall it is very effective. After all, ev n humans mispronounce words now and then!