I was redirected here from this meta post.
I can understand the need to come up with a term other than desexing, if it is inappropriate; but I can't understand the reasoning behind making neuter a synonym of spay (or vice versa).
Despite lexicographical evidence, I have always known neuter to be a specifically male term and spay to be a specifically female term. Where I live, I've never heard anybody refer to spaying a male animal or neutering a female animal.
It would be kind of like saying that man is a synonym of woman (or vice versa) rather than saying that each is a synonym of human.
I would suggest picking something like sterilization as a better word for desexing. And then making both neuter and spay synonyms of that instead.
But whatever word you pick as an "umbrella" term, I don't think that either neuter or spay should be synonymous with the other.
Update: Spurred by comments, it appears that my "common knowledge" of the two words has been incorrect.
I was raised to specifically associate one gender with each word. (And this was reinforced by vets I've dealt with here in Canada.) But the dictionary has something different to say.
Merriam-Webster specifically states that spay is associated with female animals:
: to remove the ovaries and uterus of (a female animal)
However, its definition of neuter "redirects" to castrate, which in turn refers to both sexes:
2 a : to deprive of the testes : GELD
b : to deprive of the ovaries (see OVARY 1) : SPAY
(More interestingly, I've never heard of the word castrate applied to females before either.)
Given this, it does indeed seem to make sense that neuter should be the main word, and spay a synonym of it.
But it still sounds "off" to me—perhaps the words have different regional uses.
Here is some copy from the website of Parkland Veterinary Clinic:
Specifically, spaying is the surgical removal of the uterus and ovaries and, on the other hand, neutering is the surgical removal of your pets’ testicles.
This tells me that even if usage has changed over the past forty years or so (I'm not sure if it actually has), some people still do make this distinction between the different words.