What is the plural form of “serum”?

The plural form of “serum” is “sera,” which follows a common pattern in medical and scientific terminology where certain Latin-based words have distinctive plural forms. In this case, the word "serum" comes from Latin, where the plural is often formed by changing the ending "um" to "a." Thus, "serum" becomes "sera."

The alternative option of "serums" is also used in English; however, it is considered less formal and not the preferred plural in medical contexts. Similarly, "seri" does not exist as a recognized plural form of "serum." "Serosa" refers specifically to a type of tissue lining certain body cavities and is unrelated to the plural form of "serum." Therefore, "sera" is the accurate and contextually appropriate plural form.