Sanje is a plural-only noun. The word can either refer to a series of images, ideas, emotions during sleep; a daydream; or a strong wish about the future. Basically the same as in English.
Sanje so postale resničnost.
(The dream(s) became a reality.)
Si ponoči sanjal? Se spomniš svojih sanj?
(Did you dream tonight? Do you remember your dreams?)
Danes so dovoljene sanje, jutri je nov dan.
(Dreams are allowed today, tomorrow is another day. Note – These are the famous words of Milan Kučan, the first Slovenian president, when he declared Slovenian independence.)
Ponoči sem slabo spal–imel sem hudo nočno moro!
(I slept badly tonight–I had a horrible nightmare!)
biti dekle (fant, moški) mojih sanj
(to be a very beautiful girl (boy, man) lit. – to be a girl (boy, man) of my dreams)
niti v sanjah
(to firmly deny – lit. not even in dreams)
Niti v sanjah mi ne pride na misel, da bi kupil nov avto.
(I would never buy a new car. lit – Not even in dreams would I thought to buy a new car. )
sanjati – to dream
sanjavo – dreamy
nočna mora – nightmare