A time where you tell someone about how much you love them and that you want them to be happy.

The time of day when one should make a wish while looking at the clock.

The time of the day where you make a wish and post it on a black picture with the time on snapchat. People usually add a caption, which hints towards their wish. The most used topic for 11:11 is your crush or girlfriend/boyfriend. If it's your crush, then good luck trying to get them, as it's one of the ways to not get a girlfriend/boyfriend.

( Also known as remembrance day) The 11th hour of the 11th day during the 11th month is a day where you have a minute of silence in Australia. Remembrance Day in Australia is dedicated to Australians who died as a result of war, particularly from World War I onward. A minute of silence is dedicated to the deceased, especially for soldiers who died fighting to protect the nation.
You don't use this in a sentence instead, you would say 'Lest we Forget' As a reference to this day. (This does not just happen in Australia, Other countries as well,)

The Eleventh day of the Eleventh Month. Known as Veteran's Day or Armstice Day in America. The day when World War I ended. Is also considered a holiday for some American schools.

It is the time of day where you make a wish while looking at a clock

The time of the day when middle schoolers get out of the juul room to go on snapchat and talk about some cringy shit.