Chandeliers | Pendants

Chandeliers, pendant lights, swag lamps all hang from the ceiling so what's the difference?   
Chandeliers: multiple, lower watt bulbs are used to light a room. Hardwire install. 
Pendant lights: single light, often directs light mostly downwards. Hardwire install. 
Swag lamps: The light hangs from a hook with a chain, that swags from hook to hook and then plugs in the wall. Only install are the hooks into the ceiling. 

source: mbg2021