Che (/tʃeɪ/; Spanish: [tʃe]; Portuguese: tchê [ˈtʃe]; Valencian: xe [ˈtʃe]) is an interjection commonly used in Argentina, Uruguay, Bolivia, Paraguay, Rio Grande do Sul (Brazil) and Valencia (Spain), signifying "hey!", "fellow", "guy".[1] Che is mainly used as a vocative to call someone's attention (akin to "mate!" or "buddy!" in English),[2] but it is often used as filler too (akin to "right" or "so" in English). The Argentine revolutionary Ernesto "Che" Guevara earned his nickname from his frequent use of the expression, which amused his Cuban comrades.[3]
[...] the word 'che' - meaning something like 'mate' or 'buddy'. It is used casually to grab the attention of a familiar friend, but develops an edge of impertinence if said to a figure of authority.
The Cubans were amused by Guevara's characteristically Argentine speech, peppered with the word 'che' [...]. Guevara used it to everyone. The Cubans called him 'el Che'. It stuck.