Lo, as in Lo and behold.
Libretto
I dont know a shorter word
1 : the text of a work (as an Opera) for the musical theater ( From Webster's )
Loo.
leggo!
Owl.
lasso, lotto, llano, limbo
lenovo
A seven (7) letter word that starts with M and ends with O: memento
lotto
ow
into
ox onyx
Omega.
Impasto or inferno.
fernando?