A small amount or degree; a bit.
A little child, esp. a boy.
A small boy.
A small amount, degree, extent, etc.
A tad tired.
The definition of a tad is a little amount of something, or a little boy.
An example of a tad is how sleepy you are when you just start to get tired.
(Telephone Answering Device) An answering machine.
Origin of tad
1877, "˜young or small child', probably a shortened form of tadpole. The extended meaning "˜small amount' is first recorded 1915.