What Latin abbreviation means “four times a day”?

Seen on a prescription, QID means 4 times a day (from the Latin quater in die). It is one of a number of hallowed abbreviations of Latin terms that have been traditionally used in prescriptions to specify the frequency with which medicines should be taken.
QD is once a day; q.d. stands for “quaque die” (which means, in Latin, once a day).
BID is two times a day; b.i.d. stands for “bis in die” (in Latin, 2 times a day).
TID is three times a day; t.i.d. stands for “ter in die” (in Latin, 3 times a day).