They say there is a difference.
For example, symptoms are more pronounced with the flu.
The flu is treatable, the cold is not
You can get a shot to prevent the flu, but you can’t for a cold.
Yet both a viral.
If the flu is preventable and treatable, why is the cold not?
The flu and the common cold are caused by different types of viruses - the influenza virus typically only has a couple strains going around for each flu season, thus making a vaccine for those types relatively easy to do, while there are several hundred rhinoviruses that cause colds, and people lose immunity to each type rather quickly, making vaccines for the cold impractical.
The flu is always respiratory.
A head cold may be sinus only.
MMerriam-Webster M-W.com
Main Entry: in·flu·en·za
Pronunciation: “in-(”)flü-'en-z&
Function: noun
Etymology: Italian, literally, influence, from Medieval Latin influentia; from the belief that epidemics were due to the influence of the stars
1 : an acute highly contagious disease caused by any of several single-stranded RNA viruses (family Orthomyxoviridae) and characterized by sudden onset, fever, prostration, severe aches and pains, and progressive inflammation of the respiratory mucous membrane; broadly : a human respiratory infection of undetermined cause
2 : any of numerous febrile usually virus diseases of domestic animals marked by respiratory symptoms, inflammation of mucous membranes, and often systemic involvement
Main Entry: common cold
Function: noun
: an acute disease of the upper respiratory tract that is marked by inflammation of the mucous membranes of the nose, throat, eyes, and eustachian tubes and by a watery then purulent discharge and is caused by any of several viruses (as a rhinovirus or an adenovirus)