by Edwin D. Floyd
English "stentorian" and "mentor" and their more or less immediate sources in two proper names (Stentor and Mentor) in Homeric Greek are linguistically interesting from both an English and Greek standpoint. Behind the Ancient Greek names, there is a much earlier Indo-European poetics; also, this chronologically distant Indo-European background is still faintly resonant in current English usage.
Iliad 5.785-786 refers to Sténtōr as a herald with a voice as loud as that of 50 ordinary men. The Indo-European root *sten- "to thunder" works well as background for this, and both Frisk and Chantraine, in their comprehensive etymological dictionaries of Greek, cite the proper name under their entries for Greek sténō "groan". Equally, coming forward in time, English "stentorian" is readily derived from the Homeric passage.
There is also a deeply entrenched poetic pattern, inasmuch as the related word stanáthā "roaring" appears at Rig-Veda 5.83.3, with much of the same imagery as Iliad, 5.778-792; also, the usage of English "stentorian" is still consistent with the slightly brash tinge which the Vedic and Greek passages convey for Parjanya (associated with stanáthā) and Stentor respectively.
Within English, the history of the word "mentor" seems to parallel that of "stentorian". Several times in the Odyssey, Athena appears in an advisory role as Mentor, and this lies behind Fénelon's French novel Télémaque, in which Minerva (Athena), disguised as Mentor, has a consistently advisory function; then, from Télémaque, "mentor" entered English. For all this, along with the observation that the Greek name Méntōr may be cognate with English "mind", see the OED entry under "mentor"; also, the implied connection with Indo-European *men- is made by Watkins, Dictionary of Indo-European Roots.
When we turn to Frisk and Chantraine, though, it does not seem that the matter is so clear. Both include quite a few proper names, including (as already mentioned) Stentor. Neither, however, includes Mentor, inasmuch as none of the possible dictionary entries, viz., mémona "to be eager", mimnḗskō" to remind", or ménō "to remain" has the meaning "advise".
There is, however, also an Indo-Iranian dimension, which correlates poetically with Greek. Both Avestan manaoθrīš (derivable in a straightforward fashion from Indo-European *men-), as used at Yasna 44.5, and Homeric Athena-Mentor could be said to be associated with advice within a strongly "institutional" framework (evident also in Sanskrit mantrin "counselor" and its English derivative "mandarin"). Also, going further afield, it may be noted that this "institutional" nuance is still, very frequently, part of the connotation of English "mentor".