Compare two expressions about one subject:
“A learned student” — a complex conception, not an independent assertion.
“The student is learned” — a proposition asserting learning of the student.
Likewise:
“Zayd's house” — a relational phrase, hence conception.
“Zayd's house is spacious” — an assertion of spaciousness.
Including a property or relation within a description is not the same as predicating it in a proposition. This prepares the distinction between definition and proposition.