The name of this all-important symbol also demands some attention, especially as we are even yet quite undecided as to what to call it. We speak of it to-day as zero, naught, and even cipher; the telephone operator often calls it O, and the illiterate or careless person calls it aught. In view of all this uncertainty we may well inquire what it has been called in the past.[[211]]
As already stated, the Hindus called it śūnya, "void."[[212]] This passed over into the Arabic as aṣ-ṣifr or ṣifr.[[213]] When Leonard of Pisa (1202) wrote upon the Hindu numerals he spoke of this character as zephirum.[[214]] Maximus Planudes (1330), writing under both the Greek and the Arabic influence, called it tziphra.[[215]] In a treatise on arithmetic written in the Italian language by Jacob of Florence[[216]]
(1307) it is called zeuero,[[217]] while in an arithmetic of Giovanni di Danti of Arezzo (1370) the word appears as çeuero.[[218]] Another form is zepiro,[[219]] which was also a step from zephirum to zero.[[220]]
Of course the English cipher, French chiffre, is derived from the same Arabic word, aṣ-ṣifr, but in several languages it has come to mean the numeral figures in general. A trace of this appears in our word ciphering, meaning figuring or computing.[[221]] Johann Huswirt[[222]] uses the word with both meanings; he gives for the tenth character the four names theca, circulus, cifra, and figura nihili. In this statement Huswirt probably follows, as did many writers of that period, the Algorismus of Johannes de Sacrobosco (c. 1250 A.D.), who was also known as John of Halifax or John of Holywood. The commentary of
Petrus de Dacia[[223]] (c. 1291 A.D.) on the Algorismus vulgaris of Sacrobosco was also widely used. The widespread use of this Englishman's work on arithmetic in the universities of that time is attested by the large number[[224]] of MSS. from the thirteenth to the seventeenth century still extant, twenty in Munich, twelve in Vienna, thirteen in Erfurt, several in England given by Halliwell,[[225]] ten listed in Coxe's Catalogue of the Oxford College Library, one in the Plimpton collection,[[226]] one in the Columbia University Library, and, of course, many others.
From aṣ-ṣifr has come zephyr, cipher, and finally the abridged form zero. The earliest printed work in which is found this final form appears to be Calandri's arithmetic of 1491,[[227]] while in manuscript it appears at least as early as the middle of the fourteenth century.[[228]] It also appears in a work, Le Kadran des marchans, by Jehan
Certain,[[229]] written in 1485. This word soon became fairly well known in Spain[[230]] and France.[[231]] The medieval writers also spoke of it as the sipos,[[232]] and occasionally as the wheel,[[233]] circulus[[234]] (in German das Ringlein[[235]]), circular
note,[[236]] theca,[[237]] long supposed to be from its resemblance to the Greek theta, but explained by Petrus de Dacia as being derived from the name of the iron[[238]] used to brand thieves and robbers with a circular mark placed on the forehead or on the cheek. It was also called omicron[[239]] (the Greek o), being sometimes written õ or φ to distinguish it from the letter o. It also went by the name null[[240]] (in the Latin books
nihil[[241]] or nulla,[[242]] and in the French rien[[243]]), and very commonly by the name cipher.[[244]] Wallis[[245]] gives one of the earliest extended discussions of the various forms of the word, giving certain other variations worthy of note, as ziphra, zifera, siphra, ciphra, tsiphra, tziphra, and the Greek τζίφρα.[[246]]