World is a common name for the existence of human civilization on the planet earth. In this case, the world is visualized as the earth, globe, planet or sphere.
World can also denote a feature , such as a sphere of humanity activity or interest . There are many short phrases which include the term 'world'. Examples of these phrases are: the world of economics, the world of sports, the world of entertainment etc. (By the way, 'world' is in the title of my latest book, 'Your Health in a World of Conflict'.)
Generally speaking, people having only a secular view, 'world' would only pertain only to a tangible or physical matter. This perspective strictly denotes attitudes, activities, or other things having no religious or spiritual basis.
On the other hand, there are individuals who are completly aware of the physical realm but also understandand and believe that in a theological context, world usually refers to realms or dominions which are intangible and nonphysical,such as the celestial, spiritual, transcendent or sacred. Simply put, anything secular relates to the physical world and not to the spiritual world. If there’s no supernatural manifestations involved with your things, activities or attitudes, then you’re in ‘the secular world’.