Philosophers have debated this question for centuries — you have to make your own choice as to what it means to you. There is no final or absolute answer to the question.

For me, free will is simply the ability to choose rationally among competing alternatives, coupled with the idea that you are then responsible for the results. It is of no consequence if your choices are limited sharply by circumstances, or if (being a rational person) you would always make the same or similar choices in similar circumstances.

I reject any form of predestination, and I am happy that there is enough randomness at lower (perhaps quantum) levels to ensure that no event can ever precisely duplicate itself. This ensures that even a computer program can yield different results at different times, and leaves the human mind with plenty of degrees of freedom.

We conduct our affairs as if there were free will; it works; enough said.