* -o: This is the most common ending for masculine nouns, adjectives, and articles. Examples: el libro (the book), el gato (the cat), rojo (red).
* -ión: This ending is common for masculine nouns. Examples: la acción (the action), la canción (the song).
* -or: This ending is common for masculine nouns, often denoting a person or a profession. Examples: el actor (the actor), el doctor (the doctor).
* -án: This ending is common for masculine nouns, often denoting a person or a place. Examples: el mexicano (the Mexican), el volcán (the volcano).
However, there are exceptions to these rules. Some masculine nouns end in -a, -e, or other endings. It's important to note that the gender of a word is not always predictable based on its ending. You will need to learn the gender of each word individually.
Here are some examples of masculine nouns that end in -a, -e, or other endings:
* -a: el mapa (the map), el día (the day)
* -e: el coche (the car), el jefe (the boss)
* -y: el rey (the king), el pañuelo (the handkerchief)
* -z: el lápiz (the pencil), el juez (the judge)
Important: It's also important to remember that some words in Spanish can be both masculine and feminine, depending on their meaning. For example, "el puente" (the bridge) is masculine, but "la puente" (the bridge) is feminine, if referring to a type of stitch.
To be sure of the gender of a word, you should always refer to a dictionary or other reliable source.