An English teacher once told me that in Chaucer's day the word "venerie" referred to matters involving either hunting or love; and that by saying the Monk "lovede venerie," Chaucer definitely meant he was both a hunter and a lover. I eventually discovered that that statement may be somewhat inaccurate; the modern word "venery" can refer to either hunting or love, but the two meanings derive from very different roots, and in Chaucer's time they may have been spelled differently. (In which case Chaucer may have intended the pun anyway, but the double meaning is not as clear-cut as I was originally told.) In a sense, the sequence of letters spelling "venery" actually represents two different words; it's mere coincidence that the two are spelled and pronounced alike.
I encountered several other words that are spelled and pronounced just like words of entirely different lineage, and eventually started to collect them. In English, it turns out there are quite a lot of them. Of course, like any category of words, this category needed a name; so I started looking at related concepts, hoping they could help:
- Two words that are pronounced alike, but not necessarily spelled alike, are called homophones: "rain" and "reign," for instance, are homophones.
- Two words that are spelled the same way but (a) mean different things, (b) come from different roots, or (c) are pronounced differently, are called homographs. "Wind," for instance, can refer to air in motion or to the action of tightening a spring.
- Two words that come from different roots can be described as heteroradical.
- And two words that are pronounced and spelled the same but mean different things are called homonyms.
So two words that are spelled the same, and pronounced the same, but mean different things and are derived from different roots, could be called "heteroradical homonyms." But that's a mouthful; so around here we just call them "homomorphs," words that have "the same shape." It's not a precisely accurate term, but after all, few terms are precisely accurate. The terms "homoglyph" and "hetymon" are also occasionally used as synonyms for "homomorph." ("Hetymon" being a portmanteau word roughly short for hetero-etymon, a neologism intended to mean "different source words.")
A strong homomorph has at least two same-part-of-speech meanings. A weak homomorph's meanings are all different parts of speech.
- "Mail" meaning what the Post Office delivers has a different etymology from "mail" meaning armor.
- The kind of "pool" that you can bet in doesn't come from the same root as the kind that you can swim in.
- A "riddle" meant for answering has a different derivation from one meant for sifting.
It can be hard to determine whether two words have different etymologies. Even widely divergent meanings often derive from the same root, and many etymologies are hard to guess; as they say, etymology by sound is not sound etymology. Often, stories that we hear about the origin of a word don't have any proven basis in fact. I tend, therefore, to depend on what various reliable dictionaries say about word derivations, with the OED usually being my final arbiter on debated questions. My current list of homomorphs is rather ad hoc; I'm sure there are many homomorphs that aren't on the list, and if you send me particularly cool ones I'll add them.
One final point: homomorphs have some overlap with, but are not the same as, hobson-jobsons. A hobson-jobson is a word derived from a foreign phrase, when people who don't speak the foreign language try to interpret the phrase in their own language. For instance, in the phrase "ten-gallon hat," the "gallon" part is etymologically unrelated to the word "gallon"; English speakers heard a Spanish word and interpreted it as the English word "gallon." But that sense of "gallon" is never used as a word on its own (without being prefaced by "ten"), so I don't count it as a homomorph.