1. [Medicina] quatro vezes ao dia; de 6 em 6 horas ◼ Sinônimos Inglês quarter in die; ◼ Sigla em inglês QID (quarter in die) Significado Quater in die (on prescription): Seen on a prescription, qid (or q.i.d.) means 4 times a day (from the Latin quater in die). The abbreviation qid or q.i.d. is also sometimes written without a period in capital letters as "QID".