The Spanish word 'cilantro' comes from the Latin word 'coriandrum', which itself was borrowed from Ancient Greek 'koriandron' (κορίανδρον), all meaning 'coriander'. In Spanish, the word first appeared as 'culantro', and through a common phonetic change where 'u' shifted to 'i', it became 'cilantro', which is now the standard form in most Spanish-speaking regions.

In Spanish, you might also encounter 'culantro', which is a variant form of the same word. While 'cilantro' is more commonly used to refer to the familiar herb (Coriandrum sativum), 'culantro' is sometimes used to refer to a different but related herb (Eryngium foetidum). Both words share the same etymological root and showcase how pronunciation variations can lead to different standard forms.

English speakers might recognize the connection to the word 'coriander', which comes from the same Greek and Latin roots as 'cilantro'. In fact, 'cilantro' has been borrowed directly from Spanish into English, where it's often used specifically to refer to the fresh leaves of the plant, while 'coriander' typically refers to the dried seeds in American English. This distinction showcases how related words can develop specialized meanings in different languages.