The Old English name is _buttorfleoge_, and there is a similar Dutch word; it is thought to come from a very old folk-belief that butterflies stole milk and butter. There is a possible alternative etymology in Britain that it simply refers to "butter colored fly", as the first English butterfly to appear in spring is the Brimstone (Gonepteryx rhamni), which has bright yellow wings. No-one really knows for sure which it is. It's possible it could have been both.

One common yet erroneous explanation for this word's origin is that it comes from flutterby. What we do know, instead, is that this word is very old (pre-8th century). It was originally buturfliogæ, a compound of butere "butter" and fleoge "fly". Why butter? Some suggest that it was due to many butterflies being yellow in color, like butter. Others believe it is based upon the yellow excrement of butterflies. Still others hold to the notion that butterflies were thought to land in kitchens and drink milk or butter left uncovered (this, interestingly, is supported by a German word for butterfly, milchdieb "milk-thief"). From the net. As author and etymologist David Feldman once asked, “who put the butter in butterfly?” The English common name did originate from the relatively simple combination of “butter” and “fly,” there’s a written old English citation for buttorfleoge, but the literal origin is lost. Some sources have erroneously suggested that the excrement of butterflies is thought to resemble butter. The problem with this, of course, is that other than to void excess water, butterflies do not excrete! Caterpillars do because they are the active growing stage, although a simple consideration of what they eat will make you wonder why anyone would consider that it, commonly called frass, resembled butter! Intriguingly, the larvae of the Jamaican Mexican Fritillary, Euptoieta hegesia hegesia (Nymphalidae), when fed exclusively on the yellow flowers of their preferred host plant, Turnera ulmifolia (Turneraceae), do excrete yellow frass! When a butterfly emerges from its chrysalis it voids its last larval meal and the waste byproducts of metamorphosis in meconium, a fluid that is most often blood colored (which would lead one to “bloodfly” not “butterfly”). More likely origins include considering the that males of the common brimstone butterfly (Gonepteryx rhamni, Pieridae) of England are butter-colored, or that, as author Samuel Jackson suggested, butterflies and the churning of butter are the simultaneous harbingers of spring, or that the word derives from the old myth that witches and fairies stole butter in the night, in the form of butterflies. The first of these is probably the most likely explanation (I’m a firm believer in simple explanations) but there is some etymological evidence for the last. Regardless, the word – at least in English – is unique (see So, What's in a Name (below) for more information) although I find that it has posed some interesting problems. Think about this: its common to call birdwatchers “birders” but what would one call a butterflywatcher? A butterflier? I don’t think so. It sounds too much like a food fight to me. And I can’t say I’m particularly enamored of the alternatives, lepper or bugger, either! Have you ever wondered what they call butterflies in languages other than English? I thought that I knew quite a few of them until I found this list! http://www.aworldforbutterflies.com/etymology.htm this link includes more languages http://www.trismegistos.com/IconicityInLanguage/Articles/Beeman.html

lynne and ala done did good jobs, I can't improve on their answers, unless you were asking about some specific butterfly named Ralph or something, then I'd have to say " Um...I'm not sure." I did find some translations of some of the non-English words. Many of the European ones are related to the "butter, milk, or cream thief" idea, so there might be something to it. I guess in these days when most of us don't set cream and milk out for the butter churning we don't do, we just don't see butterflies taking a taste, I do know that they will take a taste of other liquids that are spilled or dripped, or from the rim of a glass and even the lip of a beer bottle. So who knows? Most of the words seem somehow fitting for the gentle flitting and floating and general sense we have of the butterfly, I especially liked that Albanian " Flutura." Unfortunately I also stumbled across the etymology of "Moth" which is related to "maggot" bleh. And speaking of 'bleh', yellow frass? frass!? whaddaya know, even I can learn sumpin new everday. But in the area of that meaning for butterfly, and I suppose the frass area is under any tree with a bunch of frassin caterpillars in it, I find the Flemish word for butterfly,"boterschijte," which translates just like it sounds. But then I have some problems with things Flemish anyway, especially in the spring when I am more likely to encounter butterflies, flowers and their pollen. So any way here are a few 'translations' Ancient Greek- Psyche- spirit, soul (in mythology Psyche was the human lover of Eros, after her death she was given immortal life) Modern Greek - petaloudia- related to words for petal, leaf, spreading out Latin- papilio or papilionis- associated with other 'wing' and 'spreading' words, (pavilion) French- papillon- from the Latin (many Romance (Latin based) languages use variations of this, Grimm's Law in Linguistics states, simply put as it applies here, that the Southern European 'P' becomes an 'F' in northern more Germanic languages, so many of those words are from the same root. so we get things like Hungarian 'pillango', Anglo-Saxon 'fifoldara', Old English 'fifalde, Old German 'fifaltra, Norse 'fifrildi' and possibly the Irish 'feileacan.'. ( BTW the book, and movie, 'Papillon' is an autobiography of a man called Papillon, because of a tattoo, who is sent to Devil's Island, so the title is also a metaphor for the 'free spirit' in a hellish prison.) Italian- farfalla- Italian for some reason uses Grimm's 'F' instead of the Latin 'P', that pasta that we call bow-ties are really butterflies, but just try to get your kids to eat all their butterflies. Russian-babochka- now this does mean 'bow tie,' and somehow is related to 'babushka'-'grandmother' and all its relatives, baba - woman, babka-cake etc. The Russians also use 'dushichka'- from 'dusha' - 'soul.' Spanish-mariposa-possibly from "la Santa Maria posa" = "the Virgin Mary alights/rests." Polilla is Spanish for moth. Portuguese- borboleta- convoluted from papilio, mariposa are butterflies and moths, moths are 'traca' which are also silverfish. ( Crazy Portuguese!) Norwegian-sommerfugl- summer fly or summer bird (German Vogel= bird) Yiddish -zomerfeygele- summer bird, there's that Vogel again. Mandarin- hu tieh-'tieh' is the word for 70, the name is a reference to 70 years, for some reason the Chinese see the butterfly as a symbol for longevity. They also represent young men in love, possibly because of the flitting from blossom to blossom. In Japan butterflies represent young maidens and marital happiness, I guess some marriages feel like 70 years, but that wouldn't be the ones with 'happiness.' German- Tagfalter- Day Folder, Nachtfalter ( night folder) is a moth, The falter part also reflects Old German fifaltra from papilio. But my favorite is the German Schmetterling. Schmetten means cream, Schmettern, with the 'R' means 'to warble or twitter,' the word for how a bird sounds may come from the way a butterfly looks. Especially since the Latin pipilare also means to twitter or chirp. Words are way weird, with meanings just flitting from here to there and then back again all over the lexigarden. I like schmetterling because of an old joke. A bunch of stereotypical multi-national cosmopolitan types are sitting around, arguing about how much more beautiful sounding and meaningful each ones own language is than the others. Englishman-" Butterfly! When you hear it you see it fluttering by." Greek- "Petaloudia. You can see the gently spreading flowers of its wings." French- " Papillon. It floats from the tongue as quickly but gently as it does from the flower." Spaniard-"Mariposa ! It settles as gently on the ear as it does the blossom, and reminds us of the love of the Holy Mother." Bullet headed Prussian- Slams his fist on the table and shouts, " Unt vhas iss vrong mit SCHMETTERLING !?! You can find some more meanings and compare international 'moth,' 'caterpillar,' 'pupa' and other butterfly related words (but not silverfish, but I think the Portuguese relate the two because of etymological, not entomological, relationships to powder or dust. But then they also use the same word for caterpillars and lizards, maybe they are crazy.) You can also learn that the Naga trace their ancestry to butterflies, that the Pima know the creator took the form of a butterfly while looking for a place for them to live, that the Aztecs sacrificed people to release the butterfly that is the soul (and they didn't even know any Greeks) and some other stuff at http://www.insects.org/ced4/etymology.html

Believe it or not, because it was first done by butterflies.

not sure exactly. do know it was called the flutter-by. changed to butter-fly in the mid to late 1800's.

I've seen two possible answers - 1/. Their faeces look like butter 2/. They were thought to steal butter The first is believable, if a bit of a stretch. The second might be due to their obtaining salts and minerals from open curds in a bucket. Basically, both could be right. Or not.

Some say it was just a switch of the letters from the word 'flutterby'. Others say the Anglo-Saxons used the word 'butterfloege' because their most common butterfly was the yellow brimstone butterfly. This English influence was brought to the new world. In the colonies, people claimed that at night witches would turn into winged creatures and steal butter. In other languages the butterfly's name means 'licker of milk' and milk thief. So maybe they were not off the mark. In Russia they're called 'babochka' or 'little soul'. The ancient Greeks called butterflies 'Psyche' which also means 'soul.' Many cultures feel that when we die our souls go to heaven as butterflies. In France they are called 'papillon.' Parking tickets are called 'papillon' too, because they are big pieces of yellow paper. When they are placed under a windshield wiper they flap like a big yellow butterfly. The Sioux Indians called butterflies 'fluttering wings'. There are other stories which are not as pleasant. The Dutch word for butterfly, describes the color of when they go to the bathroom. It is a yellow drop from something that flies.

Fascinating question. I didn't know, but found this in the Answer.com dictionary: "WORD HISTORY Is a butterfly named for the color of its excrement or because it was thought to steal butter? It is hard to imagine that anyone ever noticed the color of butterfly excrement or believed the insect capable of such theft. The first suggestion rests on the fact that an early Dutch name for the butterfly was boterschijte. The second is based on an old belief that the butterfly was really a larcenous witch in disguise." http://www.answers.com/butterfly