usiku (u class, no plural)
night, nighttime (period between sunset and sunrise)
For those interested in literature, there are some denominations for the "Arabian Nights":
One Thousand and One Nights (Arabic: كِتَاب أَلْف لَيْلَة وَلَيْلَة kitāb ʾalf layla wa-layla) in Swahili:
"Alfu Lela U Lela"
"Kitabu cha Alfu Lela U Lela" or "Usiku Elfu na Moja"
https://glosbe.com/en/swh/One%20Thousand%20and%20One%20Nights (Coastal Swahili, perhaps in Kingozi dialect)
Kingozi is an ancient dialect spoken on the Indian Ocean coast between Lamu and Somalia and is sometimes still used in poetry. It is often considered the source of Swahili.
Hey i saw somewhere that you are trying to practice with native Swahili speakers on the internet. If you like, i am a native speaker myself and can help you out. Also you can use the HelloTalk app which allows you to speak with others international for free. Its really good. :)
Strictly speaking, evening and night are different concepts even in English. Of course there will be a debate on exactly when evening ends and night starts. Personally, I wouldn't accept "evening" as a correct translation for "usiku" , but don't hang me for that. It's just my personal opinion.
This may help;
Usiku = night
Jioni = evening
So, according to wiktionary, this is an uncountable noun.
I know I'm getting way ahead but I'm wondering about this. I understand the idea of it being an uncountable noun (just light "lightning" is an uncountable noun in English, even though it is a thing that you can count), but there must be some way to resolve this for Swahili speakers to be able to talk about "nights" (as we can say "bolts of lightning" or "lightning bolts")?
Do they say something like "times of night" or "instances of night" (maybe vipindi vya usiku or matokeo ya usiku), ...
... or substitute with the noun ngono (plural ngono) which my dictionary says means "nighttime", ...
... or is Wiktionary wrong and the plural of night is actually nyusiku, following the pattern of many other u- class words like uma (fork) with the plural nyuma?
No problem. Duolingo doesn't let you see any more than your five most recent notifications now (grrrrrr!) so I miss most replies to my comments now.
And yeah, I realised sometime later, that according to the rules of plural formation for the U/N class, the regular plural would be ... siku, which would obviously be confusing. Adding ny- and keeping the u- only happens when the the word is only two syllables long.