The Spanish word 'vez' comes from the Latin word 'vicis', which meant 'turn, succession, or alternation'. Over time, as Latin evolved into Spanish, the meaning remained similar but became more specifically associated with instances or occasions - as in 'una vez' (one time) or 'cada vez' (each time). The word underwent phonetic changes typical of Latin-to-Spanish evolution, with the 'vicis' becoming simplified to 'vez'.

Some common Spanish phrases using 'vez' include 'a veces' (sometimes), 'tal vez' (maybe), and 'otra vez' (again). The word is fundamental to expressing frequency and occurrence in Spanish.

While English doesn't have any direct cognates of 'vez', we do have some words that come from the same Latin root 'vicis', such as 'vicissitude' (a change of circumstances or fortune), 'vice-' (as in 'vice president', meaning 'in place of'), and 'vicar' (originally meaning someone acting as a substitute or representative). These words all carry the notion of alternation, substitution, or succession that was present in the original Latin word.