Similarly, several end-matter sections in books are appendices; several vermiform intestinal structures are appendixes.
Not that rare a class, then. Is there any term for them? I’m thinking of something along the lines of Imperfect Homonyms.
And certainly not in music.
Sounds like you could coin the word to describe this phenomenon… Quartzonym?
Japanese anime is often spelled with the accent over the e, following the rule that an E in a normally silent position needs a mark–a rule that came from French. And the default mark is an acute accent.
These days, though, it’s usually only used to avoid ambiguity, like in resumé and Moé (an anime term for manipulating sexual and relationship feelings using nurturing instincts. It’s similar to a gender reversed Florence Nightingale syndrome).
There’s a couple other examples of this, although they are not technically homonyms, since they don’t sound the same. But they’re spelled the same:
bases – base and basis
axes – ax and axis
That guy is a louse
Designed a computer mouse
Has pet louse and mouse.
Those guys are louses.
Designed computer mouses.
Have pet lice and mice.
We hates those meeces to pieces. 
(I use a trackball.)
How about
fish: a single animal, plural fish
fish: a species of fish, plural fishes
car key (singular), car keys (plural)
khaki (adjective – doesn’t have a plural)
Sure it does. Colours, like many adjectives, can be used as nouns in English. The khakis used by the British were greener in hue than those used by the Wehrmacht. And obviously your suggestion is a pair of homophones (in some dialects of English), but not homographs and therefore not homonyms.
I somehow missed the condition that the two words be homographs.
So, we want two
(a) nouns
(b) with identical spelling
(c) spoken identically
(d) with distinctly different meanings and possiblyy different etymologies
(e) that form plurals in different ways.
This narrows the field significantly since pluralisation is fairly standard in English. Irregular plurals are generally older words: ox / oxen, mouse / mice.
There are probably two different categories that we can find.
- Homonyms having the same etymology.
These are likely common words with a variety of meanings having diverged over time - one or more meanings having gained a specific usage as a different part of speech and therefore behaving differently.
I submit blind
I had to decide whether to install one blind or two blinds.
It is not acceptable to discriminate against the blind.
This second usage however is really an adjective acting as a noun and only in the plural.
- Homonyms having a different etymology.
Most likely candidates here are words recently adopted into english and retaining the plurals they had in the original language. There should be a few of these but I can’t think of any at the moment.
I think condition (d) can perhaps be relaxed a bit. Quartz appears to accept pairs such as media (newspapers, televison etc.) and mediums (psychics), which are closely related in meaning.
I don’t think blind counts because in the sense of the visually disabled, it’s a group noun and doesn’t have a plural.
It is very common in colloquial British English, at least. If someone asked me how tall I was, I would say “six foot”, not “feet”. It’s the same with other units - in certain circumstances, the singular form may be used as a plural.
ewe - ewes
you - you
The plural of Staff, is Staff surely? I’e one member of staff turned up today, twenty members of staff turned up today.
Some nouns have different plurals depending on circumstance. In the case you describe, the plural form is the same as the singular. But it is perfectly correct to pluralise “staff” as “staffs” in some situations. For example “the staff of Acme Inc. wore red. The staff of XYZ Inc. also wore red. Both staffs wore red.”
Hmm, I would still use staff for even for that circumstance, I must admit I have never heard 'staffs’used in any context.
Ack, Edit. Sorry I still can’t work out how to edit my posts…
Except for the usage of somebody staffing something, I.E - ‘Seargent Ect staffs the comand post.’
That’s an inflection of the verb “to staff”, rather than a pluralisation of the noun that we are discussing.
I admit that it would be rare to hear the plural noun “staffs” but I think that, in the example I gave, “both staffs wore red” is more correct than “both staff wore red”, which just sounds wrong unless you are talking about members of the same staff.