A previous question on the forum asks what the meaning of 'brand' is in the phrase 'brand new' and the overall view seems to be that it means fire. Ie fresh from the fire.
But what is its grammatical function of 'brand' in this phrase?
If we say it is a noun then the adjective 'new' is in the wrong place - plus no dictionaries label it as an adjective.
And if we say it is an adverb (like you would say 'very new') then no dictionaries I have looked at label it as an adverb.
Nouns can serve as adverbs, while retaining their noun meaning. Hence in "lightning fast" lightning is serving as an adverb to the adjective fast, but it does so by bringing its noun meaning to mind - we know that lightning is fast, and hence by picturing lightning, the adverbial intent is conveyed.
When it was first used "brand new" was the same; the audience would picture a brand fresh from the fire, and that would convey how extreme the novelty was, quite vividly.
Heavy use and less familiarity with brands themselves mean that it has lost the vividness it once had, but it is so commonly used as a phrase, that it still exists. If you don't know the imagery (that is, if you don't know why brand was chosen here), then it's no longer a noun used as an adverb, and instead it is just an adverb but only in this context.
Use of nouns as adverbs is common with colours ("fire-engine red", "apple green"). Other cases can be very vivid, but can also fall flat. The same is the case with other words used as parts of speech they don't normally serve.
One of my favourite sentences ever is from a children's book: "The ice thing only dripped and stared, and Ida mad knew goblins had been there." from Maurice Sendak's Outside Over There. Here the adjective mad is used as an adverb to modify the verb knew.
How wonderfully vivid! But do this too often and you will just confuse people. The context of a children's book also allows for rules to be stretched in different ways to other contexts*. Even in this beautiful case, the poetic license has sometimes been "fixed", as I have seen it quoted as "The ice thing only dripped and stared, and Ida mad, knew goblins had been there." where the inserted comma makes it more conventional in its grammar, but robs it of its impact as well as subtly altering the meaning.
As such, be very careful in using this sort of noun-as-adjective construct. To work well the imagery must be immediate, vivid and clear. It must also not clash badly with other imagery used elsewhere in the same piece.
*People often say "you have to understand the rules before you can break them". This is wrong. Truly, you have to understand which rules are actually tools, and how those tools help you, before you can decide that in some cases using those tools differently can help you more. The rules of good writing - even those of grammar which are stricter than those like "favour short, clear sentences" - are an example of those sort of rules, and those who "break" them poetically know not just what they gained by doing so, but have a strong understanding of what they gain in the majority of cases where they follow them.
Brand wouldn't be labeled as an adverb, because dictionaries list part(s) of speech based on how such words are used by themselves, not on their idiomatic usage.
In other words, I can describe something or someone as very old, or very tired, or very friendly, or very funny, so very is a bona fide adverb. But to label brand as an adverb would be misleading, because something can't be brand old, brand tired, brand friendly, or brand funny – only brand new. That's why the two-word expression gets its own entry in the dictionary.
The Oxford English Dictionary has a separate entry for brand-new, which it describes as an adjective, having the meaning ‘Quite new, perfectly new.’
Etymonline gives this rather unassertive response:
brand new
c.1570, from brand (n.). Originally it must have meant "fresh from the fire" (Shakespeare has fire-new).
Here the brand is from an "identifying mark made by a hot iron".
Though 'brand new' is a phrase, it is defined as a specific entity in all major dictionaries. Brand is not likely an adverb because it is not modifying the adjective new in that sense, rather it is synergistic with new and gives more emphasize on the newness.
