A philosophical and practical distinction is made between acquaintance knowledge and knowledge by description. Knowledge by acquaintance is knowledge acquired by "hands-on" experience rather than acquaintance through reading a description.
For instance, you are out camping and try to build a fire. If you have done this before it's easy to light some kindling and let the fire start which you follow by adding small pieces of wood followed by larger pieces of wood. This process would not come so easily if your only knowledge of fire-building was a description in a book in which you might have to use trial and error before you are successful in your endeavor of building a fire.