Uno can mean:

• The number one in the Spanish language or Italian language
• Uno (card game), a card game played with a special deck of cards. It is made by the Mattel company. The name originated from the word uno which mean the number one in Spanish which is what you say when you have one card remaining.
• Uno, a happy-go-lucky llama character from the preschool program Neon Paradise

UNO is an acronym for:

• United Nations Organization; see: United Nations