Yes, it means until/to. You can click the word to see the translation.
"until night" is not something I've ever heard as a native English speaker. What the heck does it even mean? "until tonight" as someone else suggested? "until night fall" ???
"Till/Until night" = "until tonight"; "through nightfall"; "past dusk/dark/sunset"; etc. It's not the most common way to say it, but it's not uncommon enough to sound foreign. Sounds fine to me, and I've been speaking English for just shy of 45 years.
I tried "until the night" which at least makes more sense than "until night", but it was called wrong.
Does До take the genitive case? How is it pronounced: with an ah sound or a oh sound? I mean, is до ночи pronounced like if it were a single word?
Until night rather than until tonight? Is there a different way of saying "tonight" rather than "night" in th this context?
In English I would probably say "Will you stay here till night time" but more naturally in this situation "Are you going to stay here till night time" or "Are you going to stay here for the rest of the day". Potäto, potato.
But with "till" being a colloquialism, I would expect to see "until" used in Duolingo instead... Oh well...
I don't share the assumption that Duolingo should avoid colloquialisms. Fluency in a language involves mastery of both formal and informal speech.
It's true that "till" is less frequent in formal contexts (at least in contemporary American English). But why do we view it as less formal?
The reply I hear most frequently from students is that "till" is a misspelling of " 'til" which is an abbreviation of "until".
But actually "til" existed in Old English and is found in an inscription from around 800 CE. (In the following centuries, "till", "tyl", "tylle", "tille", "tylle" are variant spellings -- standardized spelling is a very modern invention.) "Until" ("vntil", "unntill", "vntill", "untell", "untyll", etc.) doesn't appear until the 14th century and is derived from "till" by the addition of a prefix that descended from Old Norse "und".
The case of "till" is interesting because it illustrates how the attitudes that we have toward words are often based on false beliefs about their origin (and the assumption that the original form is the "correct" form).
It's taken me over a year to realise that "до" means until! It was first taught in the context of "See you later!", "See you soon!", etc. so I thought it was only used for farewells!