The Spanish word 'cotidiano', meaning 'daily' or 'everyday', comes from the Latin word 'quotidianus' with the same meaning. 'Quotidianus' itself was derived from 'quotidie' meaning 'daily', which was formed by combining two Latin words: 'quot' meaning 'how many' or 'each' and 'dies' meaning 'day'. Over time, as the word evolved from Latin to Spanish, the spelling changed from 'quot-' to 'cot-', but the meaning of something that occurs or is used each day remained constant.

A related Spanish word is 'cuota' (meaning 'quota' or 'share'), which also comes from Latin 'quot'. While 'cotidiano' refers to something happening each day, 'cuota' refers to a fixed amount or portion that is assigned.

Several English words share roots with 'cotidiano'. The word 'quotidian' is a direct cognate, meaning 'daily' or 'ordinary', though it's more formal or literary in English than 'cotidiano' is in Spanish. The word 'quota', meaning a fixed share or limit, also comes from the same Latin root 'quot'. Additionally, while not directly related to 'quot-', the 'di-' part of 'cotidiano' shares its origin with many English time-related words like 'diary', 'diurnal', and 'meridian', all stemming from Latin 'dies' (day).