prairie-oyster (n.)

"edible bivalve mollusk of the family Ostreidæ," late 13c., oistre, from Old French oistre, uistre (Modern French huître) and directly from Latin ostrea, plural or fem. of ostreum "oyster," from Greek ostreon, from PIE root *ost- "bone." It is thus related to Greek ostrakon "a hard shell" and to osteon "a bone." The h- in the modern French word is a regular development; compare huile "oil" (Latin oleum), huit "eight" (Latin octo).

Why then the world's mine Oyster, which I, with sword will open. [Shakespeare, "The Merry Wives of Windsor," II.ii.2]

Oyster-bed "place where oysters breed or are bred" is from c. 1600; oyster-knife, used for opening oysters, is recorded from 1690s. Oysterman "man engaged in rearing, taking, or selling oysters" is attested from 1550s. The common statement that edible oysters are in season only in months that end in -r is recorded by 1765.

"tract of level or undulating grassland in North America," by 1773, from French prairie "meadow, grassland," from Old French praerie "meadow, pastureland" (12c.), from Vulgar Latin *prataria, from Latin pratum "meadow," originally "a hollow," a word of uncertain origin; de Vaan suggests PIE *prh-to- "allotted."

The word existed in early Middle English as prayere, praiere, but was lost and reborrowed in 18c. from Hennepin and other French writers to describe the fertile but treeless parts of the American plains.

These are the gardens of the Desert, these

The unshorn fields, boundless and beautiful,

For which the speech of England has no name—

The Prairies. 

[William Cullen Bryant, from "The Prairies"]

Prairie dog for the burrowing rodent of the American grasslands, is attested from 1774, so called for its cry, which is like the barking of a dog; prairie schooner "covered wagon used by emigrants in freighting on the prairies and Great Plains before the construction of transcontinental railroads" is from 1841. Illinois has been the Prairie State at least since 1861. In Latin, Neptunia prata was poetic for "the sea."