Short-Term Debt
  
Debt that comes due within the next year. Simple.
Its kissin' cousin: long-term debt. Why is it even a Thing that it's within a year or less? Well, the fact that the company then has to pay off the principal it owes within the next year puts pressure on the CFO and management team to come up with places to find money. Are the debt markets liquid, happy to lend? Is the stock super-high, such that it's easier or better to just sell a piece of ownership in the company forever in return for paying off that debt?
So many thoughts to consider, so little time...or at least less than a year.