Definitions of Ada:

• noun:   an enzyme found in mammals that can catalyze the deamination of adenosine into inosine and ammonia

  Example: "ADA deficiency can lead to one form of severe combined immunodeficiency disease"

• name:  A female given name (common: 1 in 1754 females; popularity rank in the U.S.: #310)
• name:  A surname (very rare: popularity rank in the U.S.: #58848)