How do you say "address" as in a street address in Latin?
E.g.:
My address is 1600 Pennsylvania Avenue.
The standard term among living Latinists is inscriptio cursualis; that is, "the inscription that has to do with speed" or "that has to do with the course run." "Inscription" for inscriptio should be pretty clear—it's what's inscribed on an envelope or package sent through the mail. Cursualis acquired the meaning "postal" (as in "by posts" or "in stages") fairly early: in the Codex Justinianus, post-horses are referred to as equi cursuales; in the Codex Theodosianus, a ræda cursualis is a stage-coach. It's not too far a leap from there to the mail, which is, after all, the postal service.
Using this phrase to give one's address, however, would be weird. "Inscriptio cursualis mea est MDC Platea Pennsylvania" is really un-Latinate. As Tom Cotton writes,
Habito MDC Plateam Pennsylvaniam
is much more idiomatic. (I'm guessing about the accusative here.)
Everything that Joel Derfner writes is correct, but simply to say 'my address is 1600 Pennsylvania Avenue' requires no more than 'habito MDC . . . '
The Romance equivalents (adresse, indirizzo, dirección, endereço, adresă) all come from directio, with or without a prefix. I wonder whether “directio” might not be a less clumsy way of saying it in (modern) Latin.