Swingline Loan
  
You might think of loans as things that take 30 years to pay off. (See: Mortgage.) They might even be seemingly perpetual deficits you run on your credit card, where you pay a very high interest rate for renting that principal month after month.
A swingline is the oh so much shorter version of this borrowing. If a mortgage is an endless creek of nickels and dimes, a swingline loan is a tidal wave. In one of these loans, the borrower borrows a ton of cash...but for only like 2 weeks. They're "swinging" big for a short line of credit. Like...if the close for sale of a previous home isn't clicking date-wise for the purchase of a new home. That swingline loan covers the 2 weeks or so spread before everything settles down and returns to rivers of nickels and dimes.