Every year on the third Monday of February, schools and many businesses are closed in honor of the nation's founding father George Washington's birthday. However, the name and definition of the federal holiday, commonly known as "Presidents Day," remains unclear.

Unlike other federal holidays, like the Fourth of July when Americans commemorate the adoption of the Declaration of Independence in 1776, there is no universal agreement on the actual name of this holiday, exactly which presidents are being honored, or its correct spelling.

Many people refer to the holiday as Presidents' Day, but the U.S. government recognizes it as Washington's Birthday. USA.gov states that it is written as "George Washington's Birthday (Presidents' Day,)" although the website acknowledges the ambiguity surrounding the holiday. "This date is commonly called Presidents' Day and many groups honor the legacy of past presidents on this date," explains USA.gov. 

Some states honor both Washington, who was born Feb. 22, and President Abraham Lincoln, whose birthday fell on Feb. 12. Other states honor Washington and Thomas Jefferson while states observe all the presidents, reports the Washington Post.

The spelling of the name can also be confusing; it has three different variations—Presidents Day, President's Day and Presidents' Day.

The origin of the holiday dates back to 1885 when George Washington's actual birthday, Feb. 22, was declared a national holiday. However, in the early 1950s, there was a movement led by a coalition of travel organizations to create three-day weekends for federal workers by moving the celebration of some holidays to Mondays. One of the suggestions was to create a Presidents' Day between Washington's and Lincoln's birthday, which was already a holiday in some states. Only a few states tried the new arrangement, but it was not adopted across the country. Furthermore, the Illinois congressional delegation decided to honor Lincoln by expanding the name to Presidents Day, but Virginia lawmakers blocked the move to protect the prerogatives of The Father of Our Country, reports The Christian Science Monitor.