Which of the following terms means 'pertaining to or containing nitrogen'?

The term that means 'pertaining to or containing nitrogen' is "Nitrogenous." This word is derived from "nitrogen," the chemical element, and the suffix "-ous," which is used in chemistry to indicate that a compound contains a certain element. In biological and medical contexts, nitrogenous compounds are crucial, as they are often involved in the structure of amino acids, proteins, and nucleic acids. These compounds play vital roles in many processes within living organisms, highlighting their importance.

The other terms have distinct and unrelated meanings. "Nocuous" refers to something harmful or injurious, "Nullipara" is a medical term used to describe a woman who has never given birth, and "Orthodontics" refers to a specialized field of dentistry that focuses on correcting teeth and jaw alignment. Each of these terms serves its own particular purpose in the medical lexicon, but they do not pertain to nitrogen or its compounds.