“Possession” refers to the concept of specifying an object by saying who it belongs to (or with). A full explanation of Lojban possession is given in Chapter 8. A simple means of expressing possession, however, is to place a sumti representing the possessor of an object within the description sumti that refers to the object: specifically, between the “le” and the selbri of the description:
13.1) le mi gerku cu sutra The of-me dog is fast. My dog is fast.
In Lojban, possession doesn’t necessarily mean ownership: one may “possess” a chair simply by sitting on it, even though it actually belongs to someone else. English uses possession casually in the same way, but also uses it to refer to actual ownership or even more intimate relationships: “my arm” doesn’t mean “some arm I own” but rather “the arm that is part of my body”. Lojban has methods of specifying all these different kinds of possession precisely and easily.