E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Andrew,
a name commonly used in old plays for a valet or man-servant. Probably a Merry Andrew is simply the mirth-making Andrew or domestic jester. (See MERRY ANDREW.)
1
Similarly, Abigail is used in old plays for a waiting gentlewoman. (See ABIGALL.)