Period (Full Stop) vs. Period of Time vs. Menstrual Period

[Latch]

I’ve always wondered why (in the States, where I grew up) we have three types of “periods”. We have a period that comes at the end of the sentence, called a “full-stop” by the Brits and Aussies (and others, no doubt). We have a period of time (like “the next half hour”, or a period in an Ice Hockey game). Then there’s also a menstrual period (which I kind of equate to the “period of time” part. She’s menstruating for a period of time). How did one word come by two (or three) seemingly different meanings?

Thanks.

[RealityChuck]

Well, the OED lists 32 definitions of “period” as a noun. Like any other word, it gained multiple definitions due to usage. They all derive from the French:

[a. F. période (14th c. in Hatz-Darm.) = Sp. período, It. periodo, ad. L. period-us, a. Gr. going round, way round, circuit, revolution, cycle of years, periodic recurrence, course, recurring fit of disease, orbit of a heavenly body, rounded sentence, f. around + way; in ancient L. used only of the period or cycle of the four Grecian games, and of a complete sentence; in med.L. in other of the Gr. senses.]

The first use of “period” meaning “full stop” was in 1609, and it originated in England. “Full stop” is slightly older (1596, though the example given – from “The Merchant of Venice” – is ambiguous and the first clear meaning of “the punctuation mark at the end of a sentence” is from 1665).

There is a connection with “period of time.” Also, one meaning was “completion” and another used to be “sentence” (where the punctuation mark got its name).

[MEBuckner]

From the American Heritage Dictionary of the English Language entry for the word period:

WORD HISTORY: Many may have wondered why the word period has the sense “punctuation mark ( . )” as well as several senses having to do with time. The answer to this question lies in one of the senses of the Greek word periodos from which our word is descended. Periodos, made up of peri–, “around,” and hodos, “way,” in addition to meaning such things as “going around, way around, going around in a circle, circuit,” and with regard to time, “cycle or period of time,” referred in rhetoric to “a group of words organically related in grammar and sense.” The Greek word was adopted into Latin as perihodos, which in the Medieval Latin period acquired a new sense related to its use in rhetoric, “a punctuation mark used at the end of a rhetorical period.” This sense is not recorded in English until 1609, but the word had already entered English as a borrowing from Old French in the sense “a cycle of recurrence of a disease,” first being recorded in a work written around 1425.

[Kaitlyn]

There’s a forth basic meaning for period. In science it refers again to time, but specifically it refers to the amount of time occupied by one complete cycle, for example, the amount of time it takes a pendulum to swing from one side to the other and then back again, or the amount of time between wave crests. I’ve always assumed that since menstruation occurs in regular cycles, the word originally referred to the length of time from one mestruation to the next, and somehow came to mean the act of menstruation itself.