pons

Pons, pontis, m., third declension and an i-stem: genitive plural pontium, ablative singular ponte. On a warship the pons is the gangway, and pontes in the plural can be the boardwalk voters filed across at Roman elections.

Two set pieces carry the word. Caesar's bridge over the Rhine, described in enough engineering detail that modern reconstructions have been built from it, and Horatius holding the pons Sublicius while it was cut down behind him. The odd relative is pontifex, which looks like "bridge-maker" and probably is, though Roman antiquarians were already guessing at the connection and no one has improved on their guesses. By the time we meet the office it has nothing to do with civil engineering and everything to do with the state religion.