A person is defined as "Any living thing which is aware of its ability to think."
This definition includes all 10 of the main races of All-That-Is, as well as all of the halfling races. It can also include any animals which are Yeist hosts of any of the 10 main races, or halfling races.
The word is used when referring generally to someone without knowing their race - "A person of unknown origin", for instance. The plural is "people", which is more commonly used to refer to the thoughts of a group which could include multiple races: "All the people in Nomad's Land were affected by the earthquake", for instance.