Meaning:

• "Uno" in Spanish means "one" and is primarily used as a number. However, it can also function as a pronoun to mean "one" when referring to an unspecified person or thing.

Usage of "Uno":

1. As a Number (One):
   • "Uno" is used to count or indicate the quantity "one."
   • Example: Tengo uno. (I have one.)
   • When counting or listing items, "uno" is used in its full form.
   • Example: Uno, dos, tres... (One, two, three...)
2. As a Pronoun (One/Someone):
   • "Uno" can be used to refer to an unspecified person, similar to "one" or "someone" in English.
   • Example: Uno nunca sabe. (One never knows.)
   • This usage is more formal or literary.
3. Gender and Agreement:
   • When used before a masculine singular noun, "uno" typically shortens to "un."
   • Example: Un coche (One car) instead of Uno coche.
   • When referring to a feminine noun or when standing alone, "uno" does not change.
   • Example: Tengo una hermana y uno hermano. (I have one sister and one brother.)
4. Special Contexts:
   • Uno as a pronoun: "Uno" can be used in contexts where you want to speak in general terms about people or oneself.
     • Example: Uno debe ser amable. (One should be kind.)
   • Before Nouns Starting with 'a' or 'ha': Unlike "el" and "la," "uno" does not change when it precedes a noun that starts with a stressed "a" or "ha."
     • Example: Uno águila (One eagle) would actually be Un águila.

Example Sentences:

1. As a Number:
   • Tengo uno. (I have one.)
   • Quiero uno de esos. (I want one of those.)
2. As a Pronoun:
   • Uno debe estudiar para aprender. (One must study to learn.)
   • Cuando uno está cansado, debe descansar. (When one is tired, one should rest.)
3. Shortened Before Masculine Nouns:
   • Compré un libro, no dos. (I bought one book, not two.)

Distinguishing "Uno" from "Un":

• "Uno" is used when the number or the concept of "one" stands alone or when it functions as a pronoun.
  • Example: ¿Cuántos tienes? Solo uno. (How many do you have? Only one.)
• "Un" is used when "uno" precedes a masculine singular noun.
  • Example: Un hombre entró en la tienda. (A man entered the store.)

Understanding the different uses of "uno" helps in both counting and referring to unspecified individuals or quantities in Spanish.