ḱm̥tóm

The numeral *ḱm̥tóm ("hundred") gave its name to the centum-satem classification, the most widely known typological division within Indo-European. The word itself is generally analysed as a derivative of *déḱm̥ ("ten"), with the morpheme *-tóm indicating a multiplicative or collective: roughly "a unit of tens" or "a great ten." Latin centum ("hundred") is the form that names the centum group. The initial c- (pronounced [k] in Classical Latin) reflects the merger of the palatal *ḱ with the plain velar *k. Derivatives include century, cent ("a hundredth"), percent, centenary, centennial, centimetre, and centurion. Greek hekatón (ἑκατόν) shows a prothetic he- and the regular centum treatment. Derivatives include hecatomb ("sacrifice of a hundred oxen") and hecto- (the metric prefix for one hundred). Sanskrit śatám shows the satem shift *ḱ > ś, the diagnostic that gives the satem group its name. Avestan satəm is the specific form from which the term "satem" is taken. Gothic hund ("hundred") shows *ḱ > h (via Grimm's Law applied to the merged velar). English hundred adds a suffix -red (from Proto-Germanic *-raþ-, "number, reckoning"). German hundert follows the same pattern. Lithuanian šim̃tas shows *ḱ > š, the expected Balto-Slavic satem reflex. Old Church Slavonic sŭto and Russian sto continue the Slavic form. The centum-satem division, while historically important, is now understood as an isogloss (a shared innovation) rather than a fundamental genetic split. The discovery that Tocharian (a centum language) was spoken in Central Asia — east of all satem languages — demonstrated that the centum-satem division does not correspond to a simple east-west geographical split. Nevertheless, the terminology remains standard, and *ḱm̥tóm remains one of the most widely cited forms in comparative linguistics.