Alternative and related questions:
How do you define success?
What exactly does the word 'failure' mean to you?
The meaning behind the question:
This is an interesting question clearly designed to identify how, in the workplace, you define success but also to give the interviewer some greater insight into your psychology and the way you think and feel about success – and what your 'value system' is.
Your answer:
Everyone knows what success means – and the Oxford English dictionary defines it formally as 'the accomplishment of an aim or purpose' or 'the attainment of fame, wealth, or social status.' This question, however, is asking what the word means to you in particular. So what does it mean to you? Everyone defines success slightly differently. For some it may be a job well done. For others, it may be reward and recognition for their efforts. What is it for you?
There are no right or wrong answers to this question but do be sure to keep your definition restricted to the workplace, unless of course your interviewer has specifically asked you for a broader definition, not just related to the workplace.
Example:
For me, success has a number of different elements. On the one hand, it's clearly having achieved a specific goal or goals – the satisfaction of a job well done, having achieved one's purpose. On the other hand, it's also the recognition of that achievement by others. Ultimately, success is a significant motivator for me – the desire to achieve success in all that I undertake and to contribute to the best of my ability.
Word of warning:
Be prepared for the interviewer to follow up this question by asking you for an example of when you've personally achieved success.