A Doctor Who specializes in weight lossis called a bariatrician.
An expert in his field is often called a specialist or an authority.
The weight of air is called atmospheric pressure. It is the force exerted by the weight of the air above a given point in the atmosphere.
The pull of gravity on an object is called weight. Weight is the force exerted on an object due to gravity and is measured in units like pounds or kilograms.
The weight of air on Earth is called atmospheric pressure. It is the force exerted by the weight of air molecules in the Earth's atmosphere on a surface.
The pull of gravity on an object's mass is called its weight. Weight is the force of gravity acting on an object due to its mass.
A flag specialist is called a vexillologist.
A vocal specialist is called a Speech Therapist
Such a specialist is known by the title of podiatrist or chiropodist.
A. Pediatricians
urologist
A climatologist
secatarist
no
A "Roundsman"
Pneumocologist
skullologist
Gastroenterologists