What is the whole nine yards?

"The whole nine yards" is a phrase used in English to denote something done completely, exhaustively, or to the fullest extent possible. The origin of the phrase is somewhat unclear and has been the subject of much debate and speculation. Over the years, numerous theories have been proposed regarding its origin, but no definitive evidence supports any particular one. Some common theories include:

1. Military: One of the more popular theories is that it comes from World War II, where fighter pilots were said to receive belts of ammunition that were nine yards long, and using the whole nine yards meant expending all their ammunition.

2. Concrete: Another theory is that it originates from the construction industry, where concrete trucks might carry nine cubic yards of concrete, thus pouring the whole nine yards would mean using up the entire load.

3. Sailing: Some etymologists have suggested it could relate to sailing, where "yards" are horizontal spars on a mast to which sails are attached. Having "the whole nine yards" of sails out might mean setting all the sails.

4. Textiles: Another possibility is linked to the fabric or textile industry, where nine yards of material might be used to make elaborate garments.

Despite these theories, no documentation from the time of the phrase's origin definitively proves any specific one. The earliest known usage in print appears to date back to the 1960s, indicating that it is likely of more recent origin. Over time, it has become a well-understood idiom in everyday English language.