a Latin saying, popular in Italy and Spain, that literally means "Cicero in favour of his own house".
Used to introduce some declaration that listeners may construe as in favor of the speaker (as opposed to discussion for discussion's sake, or in the interest of truth).
It can also be used as a preemptive admission of partiality: "Cicero pro domo sua, but I believe that Everything2 is superior in concept and content to Gnupedia".
Since there appears to be no information on the 'net about the origins of this dictum, I asked my mother (the source of All Good Classical Bits) and she says that it is the title (Cicero's speeches have titles, like In Verrem - against Verre) of a speech that Cicero gave in 57 BC, where he tried to get compensation for the destruction of his house on the Palatino. The domus had been burned during his exile.