Medical Definition of ter in die (on prescription)
ter in die (on prescription): Seen on a prescription, tid means three times a day. It is an abbreviation for "ter in die" which in Latin means three times a day. The abbreviation "tid" is sometimes written without a period either in lower-case letters as "tid" or in capital letters as "TID" or with periods as "t.i.d." However it is written, 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.
Other examples include:
Last Editorial Review: 6/9/2016
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