An aria.
Aria
Reduced paid up
That word could be aria.
There is no such thing as an "extended sentence" in grammar. "Extended sentence" is a legal term, not a grammatical term.
A cavatina is a musical term meaning a short simple song that does not have multiple verses or repetitions. A cavatina can be instrumental or vocal and is generally operatic.
That is the proper spelling of the operatic term "aria".
The term is 'aria-cabaletta'. An example being Violetta's aria from act 1 of La traviata - 'È strano! è strano……Ah! fors e lui' [aria] - 'Sempre libera' [cabaletta].
Relations.
Yes.
One possibility is sonata, although sonatas usually have 3 or more separate sections and they can have complex structures. Other possible terms might be solo, song [by name], dance [by any number of dance names], character piece, etude, prelude, nocturne, intermezzo, ballade, and there are many other possibilities.
Apnea