manoeuvre

"planned movement of troops or warship," 1757, from French manoeuvre "manipulation, maneuver," from Old French manovre "manual labor" 13c.), from Medieval Latin manuopera (source of Spanish maniobra, Italian manovra), from manuoperare "work with the hands," from Latin manu operari, from manu, ablative of manus "hand" (from PIE root *man- (2) "hand") + operari "to work, operate" (from PIE root *op- "to work, produce in abundance").

The same word had been borrowed from French into Middle English in a sense "hand-labor" (late 15c.; compare manure). General meanings "artful plan, ingenious scheme," also " an agile or adroit movement" (by a person or animal) are by 1774. Related: Maneuvers.

Coup de main, and Manoeuvre, might be excusable in Marshal Saxe, as he was in the service of France, and perfectly acquainted with both; but we cannot see what apology can be made for our officers lugging them in by head and shoulders, without the least necessity, as a sudden stroke might have done for one, and a proper motion, for the other. Reconnoitre is another favourite word in the military way; and as we cannot find out that it is much more significant than take a view, we beg leave it may be sent home again. ["The humble remonstrance of the mob of Great Britain, against the importation of French words, &c.," in Annual Register for the Year 1758] 

a digraph written also as a ligature (œ) found in Latin words and Greek borrowings into Latin, representing Greek -oi-. Words with -oe- that came early into English from Old French or Medieval Latin usually already had been leveled to -e- (economic, penal, cemetery), but later borrowings directly from Latin or Greek tended to retain it at first (oestrus, diarrhoea, amoeba) as did proper names (Oedipus, Phoebe, Phoenix) and purely technical terms. British English tends to be more conservative with it than American, which has done away with it in all but a few instances.

It also occurred in some native Latin words (foedus "treaty, league," foetere "to stink," hence occasionally in English foetid, foederal, which last was the form in the original publications of the "Federalist" papers). In these it represents an ancient -oi- in Old Latin (for example Old Latin oino, Classical Latin unus), which apparently passed through an -oe- form before being leveled out but was preserved into Classical Latin in certain words, especially those belonging to the realms of law (such as foedus) and religion. These language demesnes, along with the vocabulary of sailors, are the most conservative branches of any language in any time, through a need for precision and immediate comprehension, demonstration of learning, or superstitious dread. But in foetus it was an unetymological spelling in Latin that was picked up in English and formed the predominant spelling of fetus into the early 20c.

The digraph in English also can represent a modified vowel, a mutation or umlaut of -o- in German or Scandinavian words (such as Goethe) and a similar vowel in French words (e.g. oeil "eye," from Latin oculus).

word-ending that sometimes distinguish British from American English. In the U.S., the change from -re to -er (to match pronunciation) in words such as fibre, centre, theatre began in late 18c. and became standard there over the next 25 years at the urging of Noah Webster (the 1804 edition of his speller, and especially his 1806 dictionary). The -re spelling, like -our, however, had the authority of Johnson's dictionary behind it and was unmoved in Britain, where it came to be a point of national pride, contra the Yankees.

Despite Webster's efforts, -re was retained in words with -c- or -g- (such as ogre, acre, the latter of which Webster insisted to the end of his days ought to be aker, and it was so printed in editions of the dictionary during his lifetime). The -re spelling generally is more justified by conservative etymology, based on French antecedents. It is met today in the U.S. only in Theatre as an element in the proper names of entertainment showplaces, where it is perhaps felt to inspire a perception of bon ton.