Emeritus vs Emeriti

Some emeriti have contacted our office to ask why we are named an ‘emeritus college’ rather than an ‘emeriti college’. We all recognize that the word emeritus is of  Latin origin. Sometimes it behaves as a Latin adjective, positioned after its noun and inflecting for gender and number, as in Professor Emeritus, Professor Emerita, Professors Emeriti, Professors Emeritae. These terms function as titles, analogous to Governor General. Emeritus entered English in the mid 18th century and is by now fairly well integrated into English, included in dictionaries as an adjective. Like other English adjectives, it is positioned before the noun and does not inflect for gender or number, hence ‘emeritus professors’ and ‘emeritus college’.

In Latin, an adjective can be used without the noun it modifies; emeritus follows this pattern, as is illustrated in the first sentence of this explanation. In this usage it is classified as a noun in English and tends to show number, but not gender. The above explanation is demonstrated in the Corpus of Contemporary American English (a 560 million-word corpus from 1990–2015), which reports the number of instances of the forms in its database: emeritus–1880; emeriti–111; emerita–26; emeritae–0. The Strathy Corpus of Canadian English (50 million words) counts 114 instances of emeritus and 5 of emerita, with no instances of emeriti or emeritae. The MS Word spell checker flags emeritae as a spelling error.