La scietia è il capitano, e la pratica sono i soldati (Science is the captain, and practice the soldiers) is a phrase from Leonardo’s Notebooks (1497) (codex I.2 82a in Richter, vol. II, 290); which could describe in short da Vinci’s attitude towards to what science had been for him and in his time. James S. Ackerman (1998) has noted that science in Leonardo’s time had been predominantly descriptive. Further, Thereza Wells (2008) has also mentioned that Leonardo’s view – of what science should be – foreshadows the critical and constructive methods of modern times; those would be knowledge through experience, reason, formation of a rule and experiment. The aim of this paper is not to take any side in the question whether Leonardo had been indeed a modern scientist or mainly a late medieval product of his time, in literary terms; but its main scope is to examine what the word “science” did mean in late medieval and early modern art and artistic literature. Giorgio Vasari, for instance, in his Vite (1550 and 1568) did not use the word “science” (scienza, scienze, scienzia, scienzie) in the life of Leonardo, while he used “science” in certain others artists, having primarily the meaning of high-developed technique accompanied by theoretical support and background. Moreover, Leonardo used 18 times three types of the word “science” – scienza, scientia, scietia – in his Notebooks. Using examples from his Literary Works (edition of 1883) I would like to illustrate what the meaning of word “science” had been for Leonardo and, inevitably, his era.