Marrón vs. café vs. castaño

The Spanish language, like many others, has multiple words for the color 'brown', including 'marrón', 'café', and 'castaño'. These words are used in different contexts and regions, and each presents nuances in their usage.

Marrón

Refers to the general color brown. It's a versatile term used across many Spanish-speaking countries to describe anything from colors of clothes to animals.
Este perro es marrón.
(This dog is brown.)
Estoy buscando un suéter marrón.
(I am looking for a brown sweater.)

Café

'Café' literally translates to 'coffee' in English. As a color, it's commonly used in many Latin American countries. It represents a darker shade of brown akin to the color of coffee.
El caballo es de color café.
(The horse is brown.)
Mis ojos son café oscuro.
(My eyes are dark brown.)

Castaño

'Castaño' originates from 'castaña', which means chestnut. It specifically describes the color of chestnuts and is frequently used to describe hair and eye color.
Ella tiene ojos castaños.
(She has brown eyes.)
Mi pelo es castaño.
(My hair is brown.)

Summary

In summary, while all three terms describe variations of the color brown, 'marrón' is more universally used despite regions; 'café' tends to be darker and predominantly used in Latin America; 'castaño' often describes the hues seen in chestnuts and tends to represent medium to light shades of brown.