Other forms: daddies
Daddy is an affectionate nickname for your father. For many babies, daddy is one of the earliest words they learn to speak.
Many young children call their fathers daddy, and the word is believed to come from baby talk, or the initial sounds — da da — that a baby or toddler tends to make when she's first learning to speak. It's less common for a grown person to call her dad daddy, although some people use the childish nickname throughout their lives.