QUOTE(s8535049 @ Aug 2 2005, 01:44 AM)
if you're writing a 3/4 movement work for solo piano call it a sonata
..though a sonatina would be easier
a nocturne translates into english as "night music" or similar. typically slow, relaxing, with a clear melody over the top of changing harmonies. the irish composer john field first coined the term, but chopin is more synonymous with them now, liszt also wrote 3 called "Liebestraume: 3 Notturnos" (notturno=nocturne)
I don't know if you're joking or you're serious if you say a 3 or 4 movement work will be always and surely called sonata. The word "sonata" comes from "sonata form". Almost everything's in sonata form, the symphony is merely saying "sonata for orchestra" with just a few other different things (like they usually have 4 movements, not 3 like a piano sonata, but a lot of piano sonatas have 4 movements, too!). A string quartet, string trio, or any other work for a chamber group is also usually written in sonata form (you know what sonata form is already).
The sonata is written for many other instruments, too. Violin, cello; almost every instrument has a kind of "sonata"! Usually those instruments are accompanied by piano.
A sonata can consist of more or less than just 3 or 4 movements, some consist of only 2 movements with no separate slow section, some in 5, and sometimes they're sort of mixed up together. Liszt's sonata in B minor really consists of 4 movements, but they aren't separated and have strong relation.
A nocturne is a night piece, as a lot of other people have said, and it does usually have a melody in the right hand and accompaniment in the left (but not neccesarily broken chord-how about Chopin's E flat, Op. 9 No. 2? That seems like chords, not arpeggios).
A prelude, as the name suggests, was usually a piece created specially to be played before the main "exhibiton" or work, like an opera, but in the Romantic and 20th century periods it became an independent work by itself.
A fantasy, is a work composed freely without any specific rules and limitatons in structure.