The Spanish word 'célula' (meaning 'cell') comes from the Latin word 'cellula', which meant 'small cell' or 'small chamber'. This Latin word was formed by combining 'cella' (meaning 'cell' or 'chamber') with the diminutive suffix '-ula', which was used to indicate something small. This etymology reflects how early observers described the basic units of life as tiny compartments or chambers.

A related Spanish word is 'celda', which means 'cell' in the sense of a prison cell or a monk's chamber. Both 'célula' and 'celda' trace back to the Latin 'cella', but while 'célula' took on the biological meaning, 'celda' retained the architectural sense of an enclosed space.

Several English words share the same Latin root as 'célula'. The most obvious is 'cell', which comes from the same Latin 'cella'. Other related English words include 'cellar' (originally a storage room) and 'cellular' (relating to cells). The word 'cellule' is also occasionally used in English as a direct borrowing from Latin, meaning a small cell.