What does company culture mean to you?
Culture is defined by employee's unless it's defined by the business. I think culture is always a changing thing and you either control what you want it to be or it controls you.
You see many startups with no real "culture" and more established companies with "culture" because once you get past a certain size, if you don't define it, it will pretty much just be whatever the employees make it to be, which may not always be a good thing.
For me culture is made up of what is considered "normal" behaviour in a business and this can be both good or bad. The way we view situations and processes, how we deal with challenges can all make up "culture".
This question is very open-ended but for me culture is really what the personality of the business is :)