Meanings
- medicineNothing by mouth: nothing may be eaten or drunk.
Table 34.3: Nil per os odds ratio
2021 April 29, Couloures, K. G. and Hertzog, J. H., “Adverse Events: Risk Factors, Predictors, and Outcomes”, in Mason, Keira P., editor, Pediatric Sedation Outside of the Operating Room: A Multispecialty International Collaboration, Springer International Publishing, →ISBN, page 6692 more examples
The initial written orders should include: insulin dosage to be administered as soon as the patient appears nil per os, measure all intake and output, and obtain venous blood for measurement of blood or serum urea nitrogen, glucose, acetone […] and phosphorus.
1971, Diabetes Mellitus: Diagnosis and Treatment, volume 3, American Diabetes Association, page 252We evaluated the effect of Colestid on enteral feeding-induced diarrhea in a double-blind placebo-controlled study. Nineteen patients who were nil per os (NPO) for 5 days before initiation of enteral feeding were enrolled in the study and treatment continued for 7 days.
1998 June 29, DeMeo, M et al., “Beneficial effect of a bile acid resin binder on enteral feeding induced diarrhea.”, in The American Journal of Gastroenterology, volume 93, number 6, Elsevier, AbstractSynonyms: NPO, nil by mouth · Antonyms: per os, PO
Synonyms & antonyms
Origin
- Latinnīl“nothing”
- Englishnil per os
From Latin nīl (“nothing”) + per (“by means of”) + ōs (“mouth”), literally “nothing by mouth”.
More words from Latin
Full word history & related roots →Cite this entry
nil per os. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/nil%20per%20os
“nil per os.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/nil%20per%20os. Accessed November 4, 2026.
WatkinsX Dictionary, s.v. “nil per os,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/nil%20per%20os.
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