A French collector coined the term philately, but the word actually comes from the Greek ‘philo’ lover or fond of; ‘ateleia’ free of payment or tax. Philotely is actually the more correct rendering.

The word “philately” is the English transliteration of the French “philatélie“, coined by Georges Herpin in 1864. Herpin stated that stamps had been collected and studied for the previous six or seven years and a better name was required for the new hobby than timbromanie (roughly “stamp mania”), which was disliked. The alternative terms “timbromania”, “timbrophily”, and “timbrology” gradually fell out of use as philately gained acceptance during the 1860s. Herpin took the Greek root word φιλ(ο)-phil(o)-, meaning “an attraction or affinity for something”, and ἀτέλειαateleia, meaning “exempt from duties and taxes”, to form the neologism “philatélie”.

Source: Wikipedia