What is 'liquid gold' that Donald Trump boasted about in his victory speech?

US President-elect Donald Trump hailed his supporters Wednesday night at West Palm Beach in Florida after a stunning victory in the race for the White House, pledging to usher in a "golden age" for America. In a speech laden with patriotic rhetoric and ambitious promises, Trump declared the nation's vast reserves of "liquid gold" as key to fueling the country’s economic revival.

What did he mean by 'liquid gold'?

Trump said, "We have more liquid gold — oil and gas — We have more liquid gold than any country in the world; more than Saudi Arabia. We have more than Russia."

"We're going to be paying down debt. We're going to be reducing taxes. We can do things that nobody else can do. Nobody else is going to be able to do it. China doesn't have what we have. Nobody has what we have, but we have the greatest people, also. Maybe, that's the most important thing."

Trump’s pledge to reduce the national debt has long been a staple of his campaign rhetoric, dating back to his 2016 presidential bid when he initially vowed to eliminate the debt within eight years. However, experts cast doubt on the feasibility of these claims.

In a recent report, the Committee for a Responsible Federal Budget (CRFB), a Washington-based think tank, Trump’s goal as "almost certainly false."

"Over four years, even eliminating all spending would not be enough to pay off the debt, nor would doubling revenue collection," the CRFB said in a blog post. "Over ten years, paying off the debt would require cutting all federal spending by about 60 percent or boosting revenue by two-thirds."