Meaning of yo in Social Media

Question

I have seen several times expressions like: "10 yo just watched..."

By context I understand that is a father referring to his 10 years old son. I have seen it in Twitter by different people. Are these the initials of Years Old? is this just a Twitter thing? would anyone use that in a regular conversation?

I find surprising that he says "10 yo..." and not something like "My 10 yo..." It seems like "10yo" becomes like a name.

I could not found any information in any dictionary, not even Urban dictionary.

(I am not native English. I live in a small country in Europe)

Answer 1

This is a shorthand. It is not typical of "normal" writing.

On twitter people tend to write very short posts. They don't want to mention their child's name, for privacy reasons so use a shorthand way of mentioning someone without saying their name. You might see:

10 yo just watched ...
K just watched ... (where K is the first initial of the name)
DS just watched ... (DS is short for "dear son")

If they were writing in full they would write in full "My ten-year-old son just watched...", but twitter encourages writing short phrases, not always complete sentences.