What does it mean if something is carbon based?

When it says 'life is carbon-based', it literally means just that. All forms of life are built off of the element Carbon, which is number 6 on the Periodic Table. All life is built off of carbon. Nothing can be considered life unless it has traces of carbon. For example, DNA is the base of human life, and carbon makes up most of the DNA, so when it says 'life is carbon-based', it means that all life depends on the element carbon, nicknamed 'the element of life'.