This kanji may have descended from a representation of some kind of building, which was used phonetically for the number six.

Vocabulary

Vocabulary Reading Meaning
ろく six
六つ むっつ six things
六日 むいか sixth day of the month; six days
六月 ろくがつ June
六法 ろっぽう the six codes of law
丈六 じょうろく a kind of statue of the Buddha
六月目 むつきめ the sixth month
六つ切り むつぎり dividing into six pieces