In Spanish, the word for "pen" as a writing tool varies by region and context. The most common terms include:

• el bolígrafo: Used in most Spanish-speaking countries for a ballpoint pen.

• el boli: A common, informal term for a ballpoint pen, especially in Spain.

• la birome: Used in the River Plate region (Argentina, Uruguay, and parts of neighboring countries).

• el esfero: Common in Colombia and Ecuador.

• la lapicera: Used in South America (e.g., Argentina, Chile, Peru) and can refer to both fountain pens and ballpoint pens.

• el lapicero: Used in Central America and the Andes region.

• la pluma: Often refers to a fountain pen, but can also mean a ballpoint pen in some regions like Mexico.

The verb "to pen" (as in "to write" or "to compose") translates to escribir or componer. For example:

• Este autor ha escrito algunos de los textos más exhaustivos sobre el tema. (This author has penned some of the most thorough essays on the subject.)

• Alicia compuso la letra de un tema muy conocido. (Alicia penned the lyrics of a very popular song.)

Beyond writing tools, "pen" can also mean an enclosure for animals:

• el corral: livestock pen (e.g., for horses or cattle).

• la jaula: cage or pen (e.g., for birds or small animals).

• el redil: pen for sheep.

Common phrases include:

• La pluma vale más que la espada. – The pen is mightier than the sword.

• El escrito difamatorio – Poison-pen letter.

• Un seudónimo – Pen name.

Regional variations are significant, so the correct term depends on the country. For instance, in Spain, "boli" is widely used, while in Mexico, "pluma" is common. In Colombia and Ecuador, "esfero" is typical. The term "bolígrafo" is the most universally understood across Spanish-speaking regions.