It is often said that co-hyponyms are incompatible. For example, here's Alan Cruse:
Very often a superordinate has more than one immediate hyponym, and among these there is typically a set of terms each of which is related to all the others by the relation of incompatibility.
(Meaning in Language, 2004, p. 162.)
So, ‘apple’, ‘peach’, and ‘plum’ are co-hyponyms of ‘fruit’, and an apple is not a peach, which is not a plum, etc. They are "incompatible": that bit of fruit can't be both an apple and a peach.
However, it is also often said that co-hyponyms are not necessarily incompatible. A little later on that same page, Cruse offers this example:
For instance, queen and mother are both hyponyms of woman, but there is nothing to prevent someone who is a queen from at the same time being a mother.
I'm not so sure this is a good example, though. It implies this relation:
? A queen is a kind of woman.
But this isn't quite so. Mary, Queen of Scots became queen (just a few miles from where I type, in fact) at the ripe old age of 6 days ... which hardly qualifies as "woman"! So it leaves me wondering whether, in fact, ‘queen’ is a proper (?) hyponym of ‘woman’.
So I have been trying to come up with ANY good examples of compatible co-hyponyms, and failing in the attempt. I have done my web-searches, and while it is easy to find the theoretical position explained, as I have done above (viz., that co-hyponyms are typically but not necessarily incompatible), finding examples of the less common "compatible" sort is proving elusive.
Can anyone help me?
(P.s. I would have liked to tag this with "hyponyms" or "hyponymy", but these aren't yet in use, and I'm too new to create them.)
UPDATE [2014.01.09] : (This is prompted in part by EricS's suggestion below.)
There is a further problem with suggesting queen and mother as examples of compatible co-hyponyms, and it arises in an article by Cruse himself [D. A. Cruse, ‘Hyponymy and Its Varieties’, in The Semantics of Relationships: An Interdisciplinary Perspective, ed. by R. Green, C.A. Bean, and S.H. Myaeng (Dordrecht: Kluwer, 2002), pp. 3-21; the Google Books scan has some problems]. In it, Cruse points out that some apparent co-hyponyms belong to different taxonomic classes, and so are not co-hyponyms properly speaking.
Cruse uses the example of ‘book’ for which ‘novel’, ‘textbook’, and ‘biography’ are hyponyms, but so too are ‘paperback’, ‘e-book’, and ‘hardback’: but ‘there is no embargo on something being simultaneously a paperback and a novel’ (Cruse, ‘Varieties’, p. 4). They are not, however, ‘co-hyponyms’ since they describe different aspects of the hyperonym.
This also applies to the example I originally used above. 'Queen' participates in a taxonymy to do with status relations and involves gender (like duke/duchess, etc.), 'mother' in a taxonymy of family relationship (like 'father', 'daughter', etc.), and of course there is no problem with intersections of taxonomies, much as with 'novel' and 'hardback' both of which have a superordinate in 'book'. I am beginning to doubt, then, that Cruse was correct to assert that both "queen and mother are both hyponyms of woman". Queen is a type of (hyponym of) noble; mother is a type of (hyponym of) kindred (= family relation). Or have I gone askew here?
At any rate, I'm still having trouble thinking of "good" examples of compatible co-hyponyms!