What you're probably thinking of is the Latin phrase, "Carpe diem" made famous by a Roman poet named Horace. This phrase literally means seize or pluck the day. It generally meant to seize what day you have left, because tomorrow you may all die.
The Latin expression "Carpe Diem" translates as "seize the day". It is pronounces car-pay dee-um and is a fairly popular expression that has been used often in literature and in movies.
