middle name

noun3

1. •
   A name between the first given name and the family name or surname; a second or subsequent given name.

   • I go by David but it's my middle name; my full name is William David Mason.
   • María is a common middle name in Spanish, as in José María García.
2. •
   (Philippines) One's mother's maiden name.

   • Juan Rico Martinez dela Cruz III is my full name, where Martinez is my middle name, but people just call me "JR".
   • Maria Clara Teresita Reyes dela Cruz is my full name, where Reyes is my middle name, but you can call me Tessie or Tess.
3. •
   (figurative) A trait, activity, or action closely associated with or aptly describing a person.

   • Think twice about playing for cash because "Poker" is her middle name.
   • I won't tell anyone. "Discretion" is my middle name.