b'ak'tun - a 400-year period that the Mayans used to keep track of time

a 400-year period that the Mayans used to keep track of time, like a calendar but way more complicated and less forgiving.

The b'ak'tun is like a calendar that doesn’t give you a pass.

If the b'ak'tun was a teacher, it would fail you for sure.

The b'ak'tun is the reason why the Mayans were so good at math.