The term "heterologous nitrate reductase gene" refers to a gene that has been introduced into an organism from a different species or source, and is responsible for the reduction of nitrate. Synonyms for this term include "exogenous nitrate reductase gene", "foreign nitrate reductase gene", "non-native nitrate reductase gene" and "transferred nitrate reductase gene". These terms all describe the same concept, which is the presence of a nitrate reductase gene that has been inserted into an organism from a source outside of its natural environment or genetic makeup. The use of these synonyms can help to simplify discussions about this genetic concept and make it more accessible to a wider audience.