Alexg has got it right, in my view. However, since OP says he is waiting for someone to provide a generalized answer, here's mine.
It is hardly ever wrong to omit the article. "The Mall" is the name on the signs, so must be used: "Strand" (the formal name) is both awkward and confusing, so 'the Strand' is usual: most English towns have a few similar names.
Otherwise, there are many names that have developed from descriptions; 'London Road' is the classic example. Most towns in the Home Counties have a road that leads towards London, and refer to it as 'the London road'. Often, when street names were being given, it was named "London Road". In such a case, locals will often call it 'the London Road', while outsiders including the Post Office call it 'London Road'; I wouldn't say either was right or wrong. (Road is, in practice, the only term to which this applies: "the High Street" is usual, but so is "Church Lane is the high street in that village.")
Similar rules apply to stations, airports, roundabouts, etc. Bournemouth has a roundabout with a Frizzell office block, which everyone calls "the Frizzell roundabout". The council put up a sign saying "Frizzell Roundabout", so you can call it either. As far as I can see, all names with articles follow this rule: you can call what used to be Eastleigh Airport (the airport for Southampton) either "Southampton Airport" or "the Southampton airport". "The Southampton Airport" is not correct, but is an understandable mistake; if enough people use it, the name will change.
One last purely national point; in theory, you could refer to a railway terminus named 'Thingtown Central' as either "Central Station" or "the Central"; maybe this happens in the US. Britain has too many places like Exeter, where Exeter Central is a suburban halt, and the central station is Exeter St David's. (The explanation is historical.) So "the Central Station" would be highly ambiguous, and is never used.
In the present-day style of the US Navy (and as far as I can tell also the Royal Navy, though I cannot find a suitable link), the definite article is inserted only when giving the type of vessel— never directly before the vessel's name itself. Thus, the publicity piece entitled “Nimitz Arrives Home” opens with
More than 3,000 Sailors on board the aircraft carrier USS Nimitz …
but subsequent references are bare:
While at sea, Nimitz completed approximately 374 launches and recoveries …
"I am very proud…" said Capt. Jeff Ruth, commanding officer of Nimitz.
In vernacular English the article is both prevalent and rather longstanding in use. Early in Shakespeare's Macbeth, the first witch tells a tale:
Her husband's to Aleppo gone, master o' the Tiger:
Or consider the innumerable examples in Purchas His Pilgrimes, a 1625 book "contayning a history of the world, in sea voyages & lande-travells by Englishmen & others," at least six of which lie in this excerpt:
Why this became conventional in English is difficult to say. Perhaps it became natural because the London would clearly refer to something named after bare London— meaning the city— General Slocum was a disaster, but nothing like the General Slocum. Many large or important physical objects and features idiomatically take the article, and a ship big or important enough to take a name might be expected to do so. But articles are highly idiosyncratic; we weekend on the Isle of Wight but on Isle Royale, we sail on the Great Bear Lake though on Lake Ontario, and even climb up the Matterhorn yet up Mont Cervin— the very same mountain, just known by several names.
Proper nouns are particularly twitchy, for not only are names themselves rarely logical (e.g. the people who call themselves Nederlanders we call the Dutch; the people who call themselves Deutsche we call Germans), but the entities they represent may have a preferred “house” style that differs from the styles preferred by other substantially similar entities. Elsewhere I provided the examples of
She is a professor at The Ohio State University. She received her Ph.D. from The George Washington University, and was prepared at The Lawrenceville School.
She is a professor at Kansas State University. She received her Ph.D. from George Mason University, and was prepared at Darrow School.
She is a professor at the University of Arizona. She received her Ph.D. from the College of Charleston, and was prepared at the Milton Hershey School.
Related questions include the following:
- When to use a definite article in the name of a ship
- Using the definite article before a country/state name
- Why use “the” for oceans/seas/rivers etc. but not lakes?
- Use of definite article before phrases like Heathrow Airport, Hyde Park, Waterloo Station, Edgware Road and Parliament Square
- Why 'The' is used?
- Should “the” ever be dropped from the beginning of a name/title?
- Definite article with proper nouns, titles followed by a common noun
- Document names and proper nouns/definite articles
- Definite article before schools, colleges, and universities
Best Answer
It just depends what you mean by "phrase". The everyday sense is an expression (constituent) containing several words, and since the name of an individual person or thing can perfectly well have several words, then yes. A proper noun can be a phrase, with several words. But in such a case, we would be more likely to refer to it as a "proper name" than a "proper noun", because using the word "noun" is often taken to imply that there is just a single word there.
In the grammarians' sense of "phrase", though, a phrase can have just a single word. The subject of a sentence, for instance, is a noun phrase, and of course a sentence subject may be single word. Here, the facts of language impose a certain interpretation for "phrase".
Another instance where the facts of language impose a sense that traditional grammar may find unintuitive is coordinate conjunction. A fundamental rule for how "and" works is that the grammatical category of a coordinate constituent is the same as the category of the two constituents that were conjoined. For instance, two verb phrases conjoined by "and" make up an expression which occurs in the same grammatical contexts as a single verb phrase. This rule works quite generally, and it tells us that the coordination of two nouns, common or proper, is a noun, even though it contains several words.