The musical term that means to slow tempo is ritardando. If you'd like to slow the tempo very quickly you'd call it a molto ritardando.
Ritardando is a musical term meaning to gradually slow down in tempo.
"Largo" is a slow, plodding, heavy tempo - like the marching of elephants.
moderato e grazioso
rit. or ritard.
Andante is a musical term used to mean "at a moderately slow pace", usually approximated to "walking pace".
The terms "ritardando" and "rallentando" are both used to signify a gradually decreasing tempo.
The tempo marking, usually located near the top of the music composition, determines how many beats pre minute the pace of the song should be played at. You should use a metronome to determine this.
Lento or Ritardando
I foy mean the musical term for speed, it is Tempo, or for more specific speeds it is:(slowest to fastest)LargoAdagioAllegrettoModeratoAllegroVivacePrestoPrestisimo
The acronym OPTEMPO is a military term (operations tempo). The common musical term is "up-tempo" (faster tempo, as in jazz).
Andante- a steady walking pace, to be precise. Adagietto means a little faster than adagio. Larghetto is slow, but not as slow as Largo. note: mezzo piano means moderately soft
Accelerando