Meaning: wisdom tooth/teeth
Example: つい最近親知らず2本を抜いてもらった。 (I had 2 wisdom teeth removed just recently.)
The literal translation of the words means ‘parents do not know’. This is one of the many Japanese words that could be easily misinterpreted. Adult teeth usually start to grow and develop at ages 5 – 6, and is completed by ages 12 – 13, while wisdom teeth start growing after age 20. It’s said that oyashirazu was popularized during a time when the life expectancy was on average 50 years old. By the time a person develops wisdom teeth, the parents may no longer be around, hence the term ‘parents do not know’.