Review the complete classifications:
Human / rational: equality; identical range of instances.
Human / horse: disjointness; no common individual.
Animal / human: absolute inclusion; every human is an animal but not vice versa.
Animal / white: partial overlap; a white duck is shared, a dark horse and snow lie on opposite exclusive sides.
A real particular excludes multiple distinct instances by its own conceived identity. A relative particular is narrower than some wider concept. Zayd exemplifies both; human is a relative particular.
These distinctions prepare for the discussion of the five predicables and, later, rigorous definition.