The English word "butterfly" is believed to have originated from the Old English word "buttorfleoge". There are different theories about the etymology of "butterfly". One theory is that the name may be derived from the color or the supposed butter-like excrement of butterflies. Another theory suggests that it comes from the yellow color of many species' wings, comparing it to butter. However, none of these theories are definitive.
Regarding the association with the word "minutes" in Egypt, it seems like there may be some confusion. In the Arabic language, which is spoken in Egypt, the word for butterfly is "farasha". This doesn't seem to have a direct relationship with time or minutes. The word for minute in Arabic is "daqiqah", which is quite different.
The words "moth" and "butterfly" don't have a common etymology; they developed from different roots in Old English. The word "moth" comes from the Old English "moððe".
there is a good explanation in the german version of Wikipedia (under Schmetterling):
"Origin of the name
The German term "Schmetterling", first documented in 1501, comes from the Slavic East-Central German word Schmetten (i.e. sour cream, cream), to which some species are often attracted. In superstition, butterflies were even considered to be the embodiment of witches who were after the cream, which is also indicated by earlier names for butterflies, such as milk thief, whey stealer or similar. The English term butterfly points in the same direction and corresponds to the regionally used terms Buttervogel, Bottervagel, Botterlicker, since the animals were attracted when butter was being beaten."
The gist of the explanation is this: butterflies were believed to steal the cream found on top of the milk, when beaten to extract cream or butter. This origin of the name is more clearly visible in the german word "Schmetterling", where "Schmetten" refers to cream. The English "butterfly" could be a derived version of this very old (1500) german word.
Just pick whichever theory you like. Some support for the excrement theory may be found in the old Dutch/Flemish "boterskyter", or butter-shitter. Some roadkilled butterflies also show a lot of bright yellow goo. There are also some who claim that the original word was "flutter-by", but somehow some letters were moved around. The present Dutch "vlinder" and the Rumenian (?) "fluttering " support that, and apparently so does the French "papillom".
Butterflies are seen during the day, i.e. they are active and feed during the day, while moths are seen at night, i.e. they are active and feed at night.