TID (three times a day)
TID means three times a day. It is short for the Latin ter in die, and is also written t.i.d.; British charts and labels use TDS.
How to read it
The American Heritage Dictionary and the Minnesota Board of Pharmacy give the Latin as ter in die, and MedlinePlus lists TID as “three times a day”, an abbreviation a doctor may write on a prescription. The British form, TDS, comes from a different Latin phrase: the Minnesota list gives t.d.s. as ter die sumendum, also “three times a day”, and the Lincolnshire Partnership NHS Foundation Trust’s jargon list has TDS. TID sits between BID (twice a day) and QID (four times). ISMP’s 2019 guidelines for electronic prescribing accept TID written in capitals, without spaces or periods.
Also searched as: ter in die, t.i.d., tid meaning, tid medical abbreviation.
These pages explain what medical abbreviations and symbols stand for. They are not medical advice and give no doses: a pharmacist or prescriber can explain what any label means for you.
Look-alikes: TIW and i/d
ISMP’s list of error-prone abbreviations flags TIW (3 times a week) because it is “mistaken as 3 times a day or twice in a week”; its recommended wording is “3 times weekly”. ISMP’s 2015 list also had i/d, for “one daily”, which was mistaken as tid; the recommended wording there was “1 daily”.
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Sources
- t.i.d. (American Heritage Dictionary entry), The American Heritage Dictionary of the English Language, Fifth Edition, HarperCollins Publishers, t.i.d., abbr.
- Appendix B: Some Common Abbreviations, MedlinePlus, U.S. National Library of Medicine, TID
- Partial list of prescription abbreviations, Minnesota Board of Pharmacy, Partial list of prescription abbreviations, Minnesota Board of Pharmacy, t.i.d.; t.d.s.
- ISMP List of Error-Prone Abbreviations, Symbols, and Dose Designations (2024), 2024 edition, Institute for Safe Medication Practices, Abbreviations for Frequency/Instructions for Use: TIW
- ISMP's List of Error-Prone Abbreviations, Symbols, and Dose Designations, 2015 edition, Institute for Safe Medication Practices, i/d
- Guidelines for Safe Electronic Communication of Medication Information (2019), 2019 edition, Institute for Safe Medication Practices, Frequency abbreviations
- Meaning of abbreviations and jargon, Lincolnshire Partnership NHS Foundation Trust, carers’ support pages, Lincolnshire Partnership NHS Foundation Trust, Abbreviations, T
Last reviewed September 30, 2026 by Rory Hansen. How we research