The Spanish word 'kinder' comes from the German word 'Kindergarten', which literally means 'children's garden'. This German compound word combines 'Kinder' (meaning 'children') and 'Garten' (meaning 'garden'). When the concept of kindergarten education spread globally, many languages, including Spanish, borrowed this term. In Spanish, the word was shortened from 'kindergarten' to simply 'kinder', while maintaining the same meaning of a preschool or kindergarten educational setting.

Unlike many Spanish words that have related simpler forms, 'kinder' stands somewhat alone in Spanish vocabulary as a direct borrowing from German. There aren't any simpler or more common Spanish words that share its etymology, as it's a relatively recent borrowing that hasn't developed related forms within Spanish.

English speakers will readily recognize this word's connection to 'kindergarten', which entered English directly from German in the 19th century. The concept of kindergarten was developed by German educator Friedrich Fröbel, who chose the name to reflect his vision of a nurturing educational environment where children could grow and develop naturally, like plants in a garden. Both the Spanish 'kinder' and English 'kindergarten' preserve this educational meaning, though Spanish opted for a shortened version of the word.