The story
"[T]he gloss b’ak’tun was invented [by scholars], it is not an indigenous Maya word; the Classic Maya word was probably pik."
Etymology from Wiktionary, CC BY-SA 4.0.
Today it means: In the Maya calendar, a period of 144 000 days (20 k’atun periods): 394.25 solar years. Full definition →
"[T]he gloss b’ak’tun was invented [by scholars], it is not an indigenous Maya word; the Classic Maya word was probably pik."
Etymology from Wiktionary, CC BY-SA 4.0.