not common or ordinarily encountered; unusually great in amount or remarkable in character or kind
"uncommon birds"
"frost and floods are uncommon during these months"
"doing an uncommon amount of business"
"an uncommon liking for money"
"he owed his greatest debt to his mother's uncommon character and ability"
Rare; not readily found; unusual.
"The discovery of such an uncommon fossil in the backyard garden surprised everyone who lived there."
In plain English: Uncommon means something that is rare and not seen very often by most people.
"It is uncommon to see such clear skies in this part of the country during winter."
Exceedingly, exceptionally.
"The discovery of such an uncommon species in this remote forest was truly exceptional."
In plain English: Uncommon means something that is rare and not often seen by most people.
"It is uncommon to see such clear skies in this part of the country during winter."
The word uncommon is formed by adding the prefix un- to common to mean not shared by many people or things. It entered English as a straightforward negation of an existing adjective rather than through borrowing from another language.