HaggardHawks (“Words, language, & etymology”) posted last July about a word that is just barely hanging on at the fringe of the English wordhoard: aphercotropism. As many readers pointed out when HaggardHawks first tweeted about it, it’s not in the dictionaries, but neither did HaggardHawks make it up — its first appearance seems to be in this 1899 note in The Selborne Magazine, where it is defined as “Turning away from an obstruction.” Since then it has failed to catch on to such an extent that it is not even in the Third Edition of the OED. HaggardHawks explains its etymology thus:
First of all, the prefix aph– derives from a Greek word, apo, meaning “off” or “away from”. It’s the same root we see in words like apocalypse (which literally means “uncovered” or “disclosed”), apocryphal (literally “hidden away”), and even apology, which originally referred to a formal defence or justification, or to a personal account of a story (and so literally means “from speech”).
Secondly, the –erco– part comes from another Greek word, erkos, referring to a fence, a barrier, or a some kind surrounding wall. It only has a handful of offspring in modern English, the majority of which are fairly obscure, long-forgotten terms (the kind that HaggardHawks devours) that have found their way into the dustier corners of the OED: hercotectonic (“pertaining to the construction of walls”), poliorcetic (“relating to the besieging of cities”), and hercogamous, a botanical term describing plants that grow “barriers” between their male and female parts in order to prevent self-fertilization. Apparently.
So that only leaves the suffix –tropism, which you’ll likely recognise from words like heliotropism (“turning towards the sun”) and phototropism (“growth towards a light source”).
While I admire the pedagogical spirit and lively style, I can’t help but feel a site focused on words and etymology should have done a better job. There is no “prefix aph–,” there is a prefix ap–, which indeed derives from apo. When you put it in front of a morpheme beginning with h–, naturally you wind up with aph–. The problem following on from this is “another Greek word, erkos”; as can be seen from the examples adduced, the word is herkos (ἕρκος) with an h– (reflected in spelling by a rough breathing). One can and should be aware of this stuff even without knowing Greek; studying the etymologies in any good dictionary should do the trick. [N.b.: The post has been amended to correct the error; thanks for the heads-up, Suse!] Still, I’m glad to know about HaggardHawks (via MetaFilter), and I recommend checking it out — from this entry I learned that the planet Uranus was originally going to be called George.