Q: No grammarian I/me, but why is “head” singular as well as plural when referring to cattle?
A: In both the singular and the plural, the noun “head” has long been used numerically.
It’s used for a number of animals (“twenty head of cattle,” “each head of sheep”) as well as measuring (“two heads taller,” “leading by a head,” and so on).
The earliest written example of “head” used for a number of animals comes from an Old English land charter, according to the Oxford English Dictionary. The document contains the phrase “mid xii heafdon sceapa” (“with 12 head of sheep”).
This sense of “head” is defined in the OED as “an individual animal, esp. a herd animal.” And Oxford notes that the word is used “usually with plural unchanged after a numeral or other quantifier.”
Here are a couple of 19th-century examples in which “head” is used in reference to singular or plural animals:
“The low grounds were laid under water, and many head of cattle drowned” (from The Annual Register for the year 1772).
“Every head of cattle about the place had died” (from Anthony Trollope’s novel The Belton Estate, 1866).
But “head” isn’t used for animals exclusively. In English writing, the phrase “a head” has meant “per person” since at least as far back as the 900s, according to citations in the OED.
And this usage is still with us. A report in a British newspaper, the Independent, noted in 2000: “Delegates will start the day with a ‘coffee, tea and danish’ at £5.95 a head.”
The English word “head” has ancestors in more than a dozen old Germanic languages.
It can “probably” be traced, according to the OED, even further back to a prehistoric Indo-European root that means “cup” or “vessel.” Oxford draws a comparison to the Sanskrit noun kapāla (“cup,” “skull”).
The “shift of meaning from ‘vessel’ to ‘skull, head’ ” is in fact “quite common” in other languages, the linguist Winfred Philipp Lehmann writes in A Gothic Etymological Dictionary (1986).
Lehmann points out, for instance, that the semantic resemblance between a skull and a vessel can be seen in the nouns tête in French and kopf in German. They once meant something like “bowl” or “vessel” but today only the meaning “head” has survived.
John Ayto’s Dictionary of Word Origins says the ancient Indo-European root of “head” (kauput- or kaupet-) “probably had connotations of ‘bowl’ … as well as ‘head,’ although which came first is not clear.”
Ayto says kaput-, a variant of the Indo-European root, “seems to be responsible for the Latin word for ‘head,’ caput (source of a wide range of English words).”
Thus, our word “head” is distantly related to such English words as “capital,” “captain,” “capillary,” “chief” and (yes!) “cup.”