What does the word Apostasy mean as it is defined in the dictionary?

If the dictionary says that the meaning of the word Apostate is to turn away from the faith,beliefs ,religion and principles one used to believe in ,Doesn't that make everyone who has ever changed their religion apostates?And then aren't most religions that encourage people who are already believers to leave their faith and join them made up then of those who have become in effect apostates of their previous faith?