«الحمل بالمواطأة، نحو عمرو طبيب، وبكر فصيح»
Direct predication, such as “Amr is a physician” and “Bakr is eloquent.”
In ḥaml bi-l-muwāṭaʾah, the predicate is directly said of the subject. “Amr is a physician” attributes physicianhood to Amr himself; “Bakr is eloquent” attributes eloquence to Bakr himself.
This is commonly understood as an “is-a” form of predication: the bearer of the attribute is directly described by the predicate. A paraphrase involving “has” may be related in meaning but is not the same direct expression.