ie. You can own the surface rights, but you sell the timber rights to farmer John for 25 years. The nature of the status of the land is fixed by law, and are distinguished as being either a freehold estate or a non-freehold estate. Freehold means ownership without limitations to duration.
The acronym PDF stands for 'Portable Document Format'. This long form of the acronym still doesn't tell you a lot, but it can give you a rough idea of what we are talking about. One thing that you can grasp easily is that it's a 'Document Format'.
PDF files may contain interactive elements such as annotations, form fields, video, 3D and rich media. Rich Media PDF is a PDF file including interactive content that can be embedded or linked within the file. Interactive Forms is a mechanism to add forms to the PDF file format. PDF currently supports two different methods for integrating data and PDF forms. Both formats today coexist in PDF specification: