ANSWER: Samuel Goldstein provided the רמז found in Chazal, namely in ברכות נו:, נז:, and the word is related to פלא – “wondrous[ly big]”. But I’ve always suspected that there might be a connection to the rare word נפילים (Gen. 6:4, Num. 13:33), used to describe giants. After checking, I see that some contemporary commentators have indeed suggested this (אוצר הידיעות, דף ת”נ, דעה את ה’, דף 245). Moreover, a number of early commentators (first and foremost, R’ Yosef Bechor Shor) explain that the word נפילים itself derives from פלא, that is, all who saw them stood in awe and wonder at their sheer size. If this is so, it would reinforce the logical connection between פיל and נפיל, and the connection between both of them and פלא.
In Gen. Rabba 26:7, the Midrash relates נפילים to נפל i.e. they “knocked down the (inhabitants of the) world” (see there for other explanations, all related to נפל. But this interpretation too is obviously not hard to connect to the mighty elephant.
Not sure I understand כתר in this context, but if the intention is “top” (as a crown tops the head), it certainly fits.
Rabbi Yehoshua (Jeremy) Steinberg
I would add that there is another word for elephants in the Bible: )שנהביםII Chron. 9:20, I Kgs. 10:22), which the commentators (like Rashi and Radak) connect to the word שן (“tooth”) because elephant teeth were used for making ivory products.
Rabbi Reuven Chaim Klein