What is the difference between a ‘signature’ and an ‘autograph’? [closed]

A cashier asked my friend for her autograph when she was signing for a credit card purchase (straight-faced, so it wasn’t a joke). This seemed strange to me, as I’ve only ever heard the word “signature” used in this situation. Is this usage more common than I realized?


Solution 1:

Similar to how all thumbs are fingers but not all fingers are thumbs, an autograph is a type of signature. Per the Oxford Dictionaries:

signature

NOUN

  1. A person's name written in a distinctive way as a form of identification in authorizing a cheque or document or concluding a letter.

    ‘the signature of a senior manager’

autograph

NOUN

  1. A signature, especially that of a celebrity written as a memento for an admirer.

    ‘fans surged around the car asking for autographs’

As for the cashier, it is possible that they simply did not know the difference or even that there is a difference and, having heard another cashier making the all-too-common autograph joke, thought that it was the preferred or accepted term. Or, maybe they just aren't very good at making jokes.