Firstly, it is indeed Greek: theoi.com/Olympios/Hermes.htmlHermes: (doric. Hermeas, Hermeias), for Sermes (Sermeas, Sermeias) [1] that corresponds to sanskrit Sarameyas. She is the Bitch of the Gods, who drives the herds of souls, conducting them to their last dwelling. Hermes also inherited his tasks of The messenger of the Gods, the God of Commerce (shared with Mercurius, his Roman counterpart), his main duty of guiding travelers, and as the God of Thieves, from the Vedic entities Sarama, Panis and Pusan, which he embodied along with his son Pan [2].1. Vocabolario Etimologico della Lingua Italiana, Ottorino Pianigiani. 2. The Rigveda: A Historical Analysis, Shrikant G. Talageri, C. 10 App. 3.
http://en.wikipedia.org/wiki/Hermes#Etymology
Pavlos' now defunct website about Greek personal names (called "Etymologica: Deciphering Hellenic Names") claimed that Hermes is derived from Greek ἕρμα (herma) meaning "support, foundation", which he said is related to ἑρμηνεία (hermeneia) meaning "to interpret, to explain, to translate". The website can still be viewed and consulted at The Wayback Machine. The relevant page is featured below (look for the entry of Hermes):
http://web.archive.org/web/20120324121319/http://www.etymologica.com/page7.htm
Another source that supports the derivation from 'herma', is this informative post from the Name Facts message board:
http://www.behindthename.com/bb/fact/36287
The entry for Hermes at the Nordic Names website supports this also:
http://www.nordicnames.de/wiki/Hermes
The Dutch first names database at the website of the Meertens Institute provides an explanation that is similar to the second part of Pavlos' explanation. Their entry for Hermes states that the name is probably derived from the verb 'herméneuein' meaning "to speak, to explain". See below:
http://www.meertens.knaw.nl/nvb/verklaring/naam/Hermes
For more information about the Greek words mentioned, see the Greek dictionary at the Perseus Digital Library of Tufts University:
http://www.perseus.tufts.edu/hopper/resolveform?lang=greek&page=1&lookup=erm&type=start
http://www.perseus.tufts.edu/hopper/resolveform?page=2&lang=greek&lookup=erm&type=start
[noted -ed]