If we look into the authoritative dictionary of Sergei Ozhegov about the word "flag", then in fact we don’t know anything except what is already known. In fact, the word is ancient, and the Ozhegov dictionary reflects only its status in the modern language. A flag is a flag.
BAND, a, m. (High). Same as the banner. Scarlet banners blow.
Explanatory dictionary of the Russian language by Sergey Ozhegov.
Ancient pitchfork
Speech memory does not fail us, suggesting that the banner is somehow connected with the pulling. True, the current "flag" value makes one doubt. And in vain. The old Russian verb, which sounded like "pull", and by now has practically not changed - "pull". Therefore, according to the Russian word-formation, a banner is one who pulls together, or something that pulls together, or something that has something to do with the pulling process.
Indeed, in a number of dialects of the Russian language, especially in rural areas, the pitchfork or rake is still called here and there. According to the studies of linguists-etymologists, in ancient Russia the pole with a hook at the end was called so that it was used to pull hay into stacks or, on the contrary, to raise them.
Flagpole
And what does the banner have to do with it? Yes, just a pole (in the sense of banners) is such a good thing that if you lift it up, it will be visible to everyone. And if you also tie a piece of bright fabric to it, then in general it can be seen from afar. The greatest use of this banner, expressed in scientific language, found in the identification of military units in the battles of the Middle Ages.
The banners of that time were little reminiscent of modern banners. At first it was just a piece of bright fabric. Since, as a rule, warriors from one locality gathered under one banner, a banner recognition system appeared. Each army had its own colors, images and patterns on the fabric. Mostly flag banners were triangular in shape, but others were also found. In addition, various “bindings” could be attached to the banner: pigtails, slopes, wedges or crib. Apparently, they had some additional meaning. The banners differed in size. The main principle here was the size of the army. The powerful prince was reckoned with a multi-meter banner, which at times could not be deployed right away.
In the annals there are phraseological units that are already out of use. For example, the expression "not setting up a banner" in Old Russian can be called an attack by Nazi Germany on the Soviet Union in 1941. If the war began with an official notice, the chronicler would write: "Germany raised the banner to the Union ...". “The enemy’s banner of the slaughter” is the same as “defeating”, and “standing under the banner” is “to be in the army, on the battlefield”.
Military detachment
Quite quickly the squad itself began to be called a banner, which is quite logical. You could even say, has become a full-time unit. Here is the exact number of warriors in the banner no one will tell you. This number differed greatly depending on the area. At a later time, with the spread of Christianity, the word "banner" in the meanings of "flag" and "army" was replaced by a banner with images of saints and attributes of Orthodoxy. And the banner came out of active use.
High calm banner
And Poland, like a running regiment,
in the dust throws a banner of blood ...
A.S. Pushkin. "Borodino anniversary."
The word "banner" is now used only in speeches and texts of high style. Apparently, because it came from the "legends of old antiquity." That is, it is still a “banner”, but it sounds where it is necessary to express the special meaning of this word. In poetic lines, for example, in Pushkin.
Tax
And in the 15th century, the “banner” was a cow carcass with a severed head, legs, and a skin that was pulled together (which is logical). Actually, such a banner even became a measure for customs officers who taxed food products. The volume of products, approximately equal to a cow, was equal to one banner.
Isle
If you look at the geographical map of Russia, especially its northern part, you can see the Severnaya Zemlya archipelago in the Laptev Sea, discovered in 1913 by the expedition of Boris Viltsitsky. To the north of Starokadomsky Island, Maly Taimyr Island we will find a long (3.5 km) very narrow sandy island (usually called a scythe), which is called the Flag.
Judging by the description, it is not difficult to guess for what reasons this island in the group of May Islands received this name from the expedition of George Ushakov, who in the 1930s was engaged in mapping of Severnaya Zemlya.
Village
There is another banner on the map. This is a village in Belarus, near Mogilev. True, to be honest, in Belarusian it sounds like "Sciag", but it does not change the essence of the matter. It is impossible to explain the etymology of the name due to the lack of information, but it is most likely connected with one of the above.