A rondo is usually an old-fashioned piece of music. It is a piece of a larger work, such as a sonata or suite, and its musical form is usually ABABA, ABACA, or ABACABA. It can also be known as a rondeau, if composed by a French composer, such as Jean Philippe Rameau.
It dates as far back as the 18th century, ex. Mozart's Rondo in A Minor for piano, K 511 (1787).
A few sites say that the Moldau is in a rondo-like form with eight sections. Another says it is in ternary form. I guess, then, it has no clear-cut form, but the fact that the main theme recurs gives more reason for it to be in rondo.
The rondo form introduced in classical period is not to be confused with the renaissance rondo. It is also known as ABACADA form. The principal theme 'A' restates after each episode (B C and D as here). A popular example is Mozart's Marcia alla Turka from his piano sonata, K 331.
payphone
BACABA is the structure
A cappella
In simple definition, the form is the structure or plan of the music. In most cases, the composer sketches a skeleton of his music. The redundancy of themes and motifs play a major role in music composition. Common forms in music are binary form, ternary form, rondo form, sonata form and theme and variations.
A Rondo is defined as a musical structure where the main tune (or refrain) returns after regular departures. In musical structural analysis, each section is given a letter, such as "A" or "B". If the piece of music is "A-B-A" (theme-departure-theme), it is termed "ternary", or three-part form. Most rondos have at least two departures in the form of "A-B-A-C-A". This is known as the five-part Rondo form. The seven-part rondo includes a return of the "B" section as well: "A-B-A-C-A-B-A". More elaborate Rondo forms might have multiple departures "A-B-A-C-A-D-A", etc. It should be noted that each "A" section does not have to be stated in its entirely, but needs only to to establish the familiarity of the music before going on to another departure.
Rondo form
e means e
In music Binary, Ternary and Rondo are like the layout of a song. So say A represents a verse, B a chorus and C would represent a Bridge! Binary would be A,B (Verse, chorus) Ternary would be A,B,A (Verse, chorus, verse) Then Rondo would be A,B,A,C,A (Verse, chorus, verse, bridge, verse)