allargando

In lang=en terms the difference between ritardando and allargando

is that ritardando is gradually decelerating the tempo of a piece of music, especially at the end of the piece while allargando is decreasing in tempo; getting slower.

As an adverb allargando

is (music) decreasing in tempo; getting slower.

As a noun stringendo is

a passage in music to be played gradually faster; a section of music with in which the tempo slowly increases.

is likely misspelled.

has no English definition.

As an adverb allargando

is decreasing in tempo; getting slower.

In lang=en terms the difference between adagio and allargando

is that adagio is describing a passage having this mark while allargando is decreasing in tempo; getting slower.

As a noun adagio

is a tempo mark directing that a passage is to be played rather slowly, leisurely and gracefully.

As an adjective adagio

is describing a passage having this mark.