Origin of the word "taxi"

The German name of Taxameter, at first adopted in Britain, was taken from Taxe, a charge or levy. After the device became common in Paris..., the French created the term taximètre for it, from taxe, a tariff...

Partly in consequence of patriotic feelings, coupled with anti-German sentiment..., the French term proved popular. In the Anglicised spelling taximeter it was used in a London newspaper in 1898 even before the metropolitan meters, of the German type, had gone into operation. Taximeter soon permanently replaced the German name.

These early devices were, of course, fitted to horse-drawn hansom cabs or growlers (so called because of the noise their iron-hooped wheels made on London cobbles). There was some argument over what to call these new metered vehicles. While the official designation for any vehicle plying for hire was hackney carriage, everybody called them cabs (a short form of cabriolet, the French name for a light horse-drawn two-wheeled vehicle that had been indirectly borrowed from the Latin word for goat because of its bounding motion). A metered hire vehicle was clearly enough a taximeter cab, but this was too unwieldy for daily use.

Motorised vehicles began to appear in substantial numbers during the first decade of the new century, all being fitted with meters from the outset. In March 1907, the Daily Chronicle remarked that “Every journalist ... has his idea of what the vehicle should be called” and went on to list motor-cab, taxi-cab, and taximo among the options touted... By November 1907 the Daily Mail had begun to refer to a “taxi”, in inverted commas as befitted a colloquial term not yet admitted to the standard lexicon. In February 1908, the Daily Chronicle noted that the issue had been resolved: “Within the past few months the ‘taxi’ has been the name given to the motor-cab.” Since then, of course, it has spread greatly, though never ousting cab from the language.

That isn’t the whole story. Of the words on the list that the Daily Chronicle produced in March 1907, one other did well, though not so much in the UK. Taxicab is on record from as early as December 1907 in New York and it has survived in the US.

Found at World Wide Words, where there are additional details.