Oasis
An inn in the desert.
Letter O
Octogenarian
Applies to any elderly man.
More from Letter O
Obscenity
All scientific words derived from Greek and Latin conceal an obscenity.
Odalisques
All women in the Orient are odalisques. (See Bayaderes.)
Odeon
Joke about its remoteness.
Odor (foot)
A sign of health.
Offenbach
On hearing his name, hold two fingers of the right hand close together, to preserve yourself from the evil eye; it looks very fashionable and Parisian.