The pluralization of septum.

TO THE EDITOR: In a recent excellent study reported in the Journal that described the development of a novel threedimensional human model to study fibroblast activation during alveologenesis (12), the plural of the word septum was presented as septae. In Latin, neuter nominative and accusative nouns of the second declension, such as septum, which ends in -um, are created plural by the ending -a. Thus the correct plural form of septum (which has the alternative forms saeptum and sæptum) is septa, not septae. This applies in the nominative, accusative, and vocative cases. This error no way detracts from the outstanding scientific quality of the publication cited above. The incorrect use of septae instead of septa is not a new concern in the published scientific literature (1) and probably arises from the pluralization of first declension nouns, where the singular nominative form ends in -a and that are pluralized by ending -ae. This is not the case for septum. A brief PubMed scan of the “lung literature” over 2015 and 2016 revealed six instances of the incorrect pluralization of septum already in 2016 (2-4, 6, 9, 12), vs. four instances in the preceding year, 2015 (5, 7, 10, 11); thus the problem is “on the increase.” These instances were broadly spread over a spectrum of lung biology and medicine disciplines: clinical pulmonary radiology (4), lung developmental biology including alveologenesis and bronchopulmonary dysplasia (2, 5, 6, 11), mycobacterial disease (3), experimental studies in environmental health (9), clinical problems of fetal lung maturation (7), and vascular pathology (10). It is worth noting that the author’s own publications are not immune from this gremlin (8)! To quote Dr. Harry M. Bauer, MD: “We are beset by neologisms that we do not need” (1). It is important that we as authors, reviewers, and editors take care to prevent these neologisms from becoming accepted through increasing and widespread use in our scientific literature.