Lisa is her first name. She was born Lisa Gherardini and became Lisa del Giocondo when she got married. Mona is short for Madonna or as people would say in English: Ma'am or Madame. Lisa is Hebrew...
Mona is an Italian contraction of ma donna, "my lady". The sitter's identity is up for debate, but in his biography of Leonardo, Giorgio Vasari asserted she was Lisa di Antonio Maria Gherardini,...