"The whole month?"
Why isn't there a definite article in front of the adjective in this case? i.e. Den hela månaden?
In the sense of "the entire/whole" or "all of", only hela is used, without an article, and followed by a definite form. Same with other similar words, such as halva 'half of' or båda 'both of'. (Note the sense of measuring/specifying with these words)
If you use it with an article you'll get the other sense of the word, 'whole' as in 'unbroken'.
Hela huset = The entire house
Det hela huset = The unbroken house
I learnt that hela doesn't take a definite article because of the song Hela Huset. ;)
Bump. Is it because månaden is in definite form, and despite the phrase not requiring den, the adjective still follows the rule for definite form?
Late answer, but that's exactly it. Adjectives before definite nouns are in the definite form.
But hela is the plural form, no? Is it also the definite form? This confused me because it looked like a plural adjective with a singular noun.
Is man in manaden related to mane (Moon, I don't have accents), and how a month is Moon-based?
It is in English too, that's why it's called month. A month is approximately one moon-cycle, but it doesn't work out perfectly, which is why there can sometimes be two full moons in the same month. People were already using months to measure time in the Stone age, according to https://en.wikipedia.org/wiki/Month