Q: I’m perplexed by the spelling of “mammalogy.” Shouldn’t it be “mammology” or “mammalology,” as per “biology,” “neurology,” and other subjects of study with an “-ology” suffix?
A: You’re not the first person to question the legitimacy of “mammalogy.”
People began complaining about it soon after the word showed up in English in the 19th century, but primarily for a different reason. They were bothered that it combined a noun of Latin origin, “mammal,” with a suffix of Greek origin, “-logy.”
The English word was inspired by the French term for the study of mammals, mammalogie, which appeared in 1803, three decades before the Anglicized version made it into print, according to the Oxford English Dictionary.
The earliest English example for the word in the OED is from the first volume of the Penny Cyclopaedia, published in 27 volumes from 1833 to 1843:
“The following table exhibits the peculiar characters of American mammalogy, the manner in which the different orders are distributed … and the relative proportion which the number of American species bears to the whole number in each order.”
The next Oxford citation is from the third volume of the encyclopedia, which appeared in 1835: “Fischer, the most recent writer upon mammalogy, enumerates eleven different species of baboons.”
However, the third example (from the 14th volume of the encyclopedia, published in 1839) contains criticism of the usage:
“Vicious however as the word is, the term mammalogy is in such general use by the zoologists of England and France, that it seems to be less objectionable to retain it.”
And an 1857 citation from An Expository Lexicon of the Terms, Ancient and Modern, in Medical and General Science (1860), by Robert Gray Mayne, is also critical:
“Mammalogy, an imperfect term for a treatise or dissertation on, or a description of the Mammalia.” (The treatise sense of the term is now rare.)
The OED explains that the 1839 and 1857 citations “refer critically to the word’s formation from a prefix of classical Latin origin and a suffix of ancient Greek origin, and perhaps also to its coalescence of the last syllable of mammal with the first of -ology.”
The dictionary adds that the terms “mastology n., mastozoology n., mazology n., and therology n. were all proposed as substitutes in the 19th cent.”
Getting back to your question, why is the word “mammalogy” rather than “mammology” or “mammalology”?
Well, “mammology” would be confusing and might suggest the study of breasts (“mammo-” is a combing form for breast). And “mammalology” is awkward and a bit of a mouthful.
The word that caught on, “mammalogy,” is similar to “mineralogy” and “genealogy.” In all three words, the “a” is pronounced “ah,” so the “-alogy” ending sounds the same as “-ology.”
By the way, the OED has entries for both “-logy” and “-ology” as suffixes used to form “nouns with the sense ‘the science or discipline of (what is indicated by the first element).’ ”
The initial “o” in “-ology” words is generally considered a connective, or combining vowel. And this “o” often originates in the first element of the word rather than in the suffix.
The subject of study in “theology,” for example, is theos, Greek for God. The English word combines “theo-” and “-logy.” Similarly, the subject in “mythology” is mythos, Greek for story, and the subject in “biology” is bios, Greek for life.
As the Chambers Dictionary of Etymology explains, “the -o- is considered a connective, though in many instances it belonged to the preceding element as a stem-final or thematic vowel.” So the “o” in many “-ology” words evolved from the last letter or the key vowel of the subject of study.
In a 2014 post on the blog, we note that the ultimate source of “-ology” and “-logy” is the “Greek logos (variously meaning word, speech, discourse, reason). Added to the end of a word, -logos means one who discourses about or deals with a certain subject, as in astrologos (astronomer).”
We should also mention that the suffix is often used to form humorous nonce words, terms created for one occasion.
Here’s an 1820 example from William Buckland, an English theologian and Dean of Westminster: “Having allowed myself time to attend to nothing there but my undergroundology.” (From an 1894 biography of Buckland by Elizabeth Oke Gordan, his daughter.)
from Grammarphobia http://www.grammarphobia.com/blog/2017/01/mammalogy.html