People often say "yesterday" but never "yesternight"

People often use the word yesterday to describe the previous day but you never hear anyone saying yesternight (the previous night). Most people seem to prefer last night instead, and the same also applies for years as well (last year instead of yesteryear) but that's a whole different topic lol.

Just a random curiousity, why is this?

Because "yesternight" sounds completely retarded.

I've never heard anyone say yestermorning either

"Yesterday" can refer to any point in the previous day, so there's not really any need.

I've heard, or I should say read "yesteryear" before. Either from different books or articles in the paper.

Probably won't hear many people saying it, unless you're at a renaissance festival.

That's cause yesternight isn't a word. Not that that's ever stopped anyone from saying anything But yeah, yesternight just plain sounds ridiculous

While were on the topic, what is a yester?

I think yesteryear is a more dramatic way of saying last year, or the past. Sounds like something that would be in a promo for an old time travel movie.

I quite like the word 'Yesternight'

I say yesternight

I also like to use words like forsooth and egads.

I ate someone yesternight

They're cool words! I have yet to say 'forsooth' though.

It's great fun trying to use it in a sentence without getting strange looks

I think there's nothing wrong with using words like that, I think it's nice to be creative with language. It's one of the best things we have.

It's the way language has evolved, which is brilliant.

I believe it indicates a period of time before the present one whether it was a day, year etc.