Well, Marx defined it as an economic system characterized by private ownership over the means of production, for profit. Since then, there have been a lot more additions to the definition to make it seem more like a system where large corporations and conglomerates exploit resources and people. None of these definitions are perfect, but a system characterized by private property is good enough. Once you respect property rights, all the other things tend to follow.
Well, Marx defined it as an economic system characterized by private ownership over the means of production, for profit. Since then, there have been a lot more additions to the definition to make it seem more like a system where large corporations and conglomerates exploit resources and people. None of these definitions are perfect, but a system characterized by private property is good enough. Once you respect property rights, all the other things tend to follow.