Roger Wilco - In the shorthand used by American radio operators during World War II, "Roger" represented the letter R and stood for the word "received," as in "Message received." "Wilco" was an abbreviation of the phrase "will comply." The phrase, thus meaning, "I have received orders and will obey them," has been a staple ever since.
stroke - The usage of "stroke" to mean "cerebral hemorrhage" is curious, inasmuch as the original sense of the noun is "to touch gently." The medical term takes its meaning from an unrelated verb, though, which means "to strike hard," whether with a hand or a weapon; it has its origins in a medical text of the late sixteenth century that refers to the seizure, then called apoplexy, as "the stroke of God's hand."
horse latitudes - In the regions thirty degrees north and south of the equator, the winds are fickle: sometimes they blow hard, and sometimes they hardly blow at all. In legend, sailors whose ships were becalmed threw horses and other cargo overboard to lighten their load and move forward, but the term likely comes from the Spanish phrase golfo de las yeguas, "gulf of the mares," referring to the waters at that latitude off the coast of northwest Africa.
freak - An oddity of nature, a "freak" was originally someone whose mind twisted and turned without pattern or warning. The word comes from the Old English verb frician, "to dance," which does not survive otherwise.