This paper retraces the occurrence of the word ‘organism’ in writings of different authors from the seventeenth to the nineteenth centuries. It seeks to clarify chronological and conceptual shifts in the usage and meaning of the word. After earlier uses of the word in medieval sources, the Latin word organismus appeared in 1684 in Stahl's medico-physiological writings. Around 1700 it can be found in French (organisme), English (organism), Italian (organismo) and later also in German (Organismus). During the eighteenth century the word ‘organism’ generally referred to a specific principle or form of order that could be applied to plants, animals or the entire world. At the end of the eighteenth century the term became a generic name for individual living entities. From around 1830 the word ‘organism’ replaced the expressions ‘organic’ or ‘organized body’ as a recurrent technical term in the emerging biological disciplines.