A diminutive or nature-inspired nickname
In English-speaking contexts, Moo is almost exclusively used as a playful nickname or a term of endearment. It is often derived from names like Maureen or Muriel, or used as a whimsical reference to the sound a cow makes. In some Southeast Asian cultures, particularly Thai, Moo is a common nickname meaning 'pig', often given to babies to ward off evil spirits by suggesting the child is not overly precious.
Less common today
Moo isn't in the latest US Top 1000. It last peaked at #7,514 in 2013.
A character in the animated series Β· Monster Rancher
A school of martial arts founded by Hwang Kee
US births per 5-year period, 1990βpresent (SSA data).