In agricultural and food safety reports (particularly from Brazil), "Nitr" stands for used as preservatives:
In clinical trial data, "Nitr" is frequently used as an abbreviation for , a hypnotic drug: Search results for nitr (15)
If you tell me where you saw this, I can give you the exact definition. In agricultural and food safety reports (particularly from
In hobbyist communities (like fish keeping), it is shorthand for Nitrate or Nitrite levels. A result like "Nitr 15-20ppm" indicates a specific measurement in parts per million. Medical Research Search results for nitr (15)