I thought the definition of “dollar” was something like 132.7 grains of gold or whatever?
The question you ask is a good one and I just don’t have the answer, there are PM bugs out there who have written treatises on the lack of a legal definition of the word “dollar” in the US Legal Code, however I’m not well versed enough in it to respond.
About 10 years ago someone on FR posted a link to this guy:
Jim Ewart, President, Principia Publishing, Inc.
He wrote a book on the subject that is well regarded.
“Money – Ye shall have honest weights and measures”
Are you serious? As a matter of fact, the dollar has had no connection, absolutely no connection, to any quantity of precious metal in any way since Nixon unilaterally terminated the Bretton Woods system in 1971. This ended any convertibility of the US dollar to gold. At that time only foreign central banks had the ability to convert their dollar holdings to gold because private ownership of gold by US citizens was made illegal in 1933.
The definition of the US dollar is whatever the Federal Reserve says it is. According to Ben Bernanke, who ought to know what he's talking about, "my definition of the dollar is what it can buy".
Helicopter Ben went on, "Consumers don't want to buy gold. They want to buy food and gasoline and clothes and other things in the consumer basket, and it is the buying power in terms of goods and services that is important."
That is the only practical definition of the dollar. It is a faith-based currency, merely a unit of account consisting of one hundred cents. There are only two reasons that anybody would accept a dollar in payment or hold a dollar for the future. First, they are legal tender for payment of taxes and contractural obligations denominated in dollars. Second, there is almost universal faith that somebody else will accept dollars in return for future goods and services.
A Google search will yield a number of other dubious definitions, but if you try to use them you'll end up like Bernard von NotHaus.