As an aside, check out "Colorless green ideas sleep furiously" ( http://en.wikipedia.org/wiki/Colorless_green_ideas... ) which explains how grammatical and semantic correctness are independent. On this basis, even if "a true door" were a meaningless concept, it would still be grammatically correct as a correctly-formed "article adjective noun" combination.
How are you using it? If you are opening a door to enter a room, you are simply opening a door--you don't have to call it a "true" door, or a "real" door. (If for any reason you need to say that a door is really a door, you would use "real" or "actual" door, not "true.")
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It's 100% grammatically correct - though semantically unusual.
However, you can find examples in architectural texts: https://www.google.co.uk/search?q=%22a+true+door%2...
As an aside, check out "Colorless green ideas sleep furiously" ( http://en.wikipedia.org/wiki/Colorless_green_ideas... ) which explains how grammatical and semantic correctness are independent. On this basis, even if "a true door" were a meaningless concept, it would still be grammatically correct as a correctly-formed "article adjective noun" combination.
How are you using it? If you are opening a door to enter a room, you are simply opening a door--you don't have to call it a "true" door, or a "real" door. (If for any reason you need to say that a door is really a door, you would use "real" or "actual" door, not "true.")
i would say " a genuine manner of egress " .
a door is not a door when it is a jar .
It depends on the context, in English it always depends on the context.