In chemistry, an atom is polyvalent if it has a valence of two or more, allowing it to form chemical bonds and combine with multiple other atoms.
Polyvalent comes from the Greek polys, "much," and the Latin valentia, "strength or capacity." Polyvalent atoms have a greater capacity to connect with others and form complex molecules. In immunology, the term polyvalent is also used for drugs, vaccines, or antibodies that can fight off more than one virus or toxin.