nitrate

1. (chemistry) Any salt or ester of nitric acid.Examples: "Nitrates are most commonly used in fertilizers, especially sodium and potassium nitrates. Numerous water wells have had to be abandoned because of the lack of a way to deal with the problem."; "The underground water which feeds Britain's springs and rivers and provides a third of its drinking water is becoming seriously polluted with nitrates, causing a threat to wildlife and landing consumers with a big purification bill."; "The pinkness of bacon – or cooked ham, or salami – is a sign that it has been treated with chemicals, more specifically with nitrates and nitrites."