Is it possible you were thinking of ‘aureate’? It starts with ‘A’, it's an adjective, it's decently old, it seems decently autological, I don't think it's a common word, and here are some quotations from Wiktionary's entry on it (copied under CC BY-SA 3.0 terms; bold emphasis mine):
1996, Keith D. White, John Keats and the Loss of Romantic ...
I would add that in most forms of everyday conversation all that is needed is never referring to poetry unless in educational settings.
"The, that lyric" for specifying one line or stanza of a song
"The, those, lyrics" for an entire song
Using Google Ngram Viewer and the search terms the fruit are,the fruit is,the fruits are,and then chosing the first quote, taken from a recently published book by a native speaking author, we have
The Woody Plant Seed Manual - Page 473
United States. Forest Service, F. T. Bonner, Robert P. Karrfalt - 2008 Found inside – Page 473
The fruits are juicy , 1- ...
a rented house
a confused/bored child
Your mistake is in assuming that "rented" is an adjective here. It isn't; it's a verb. Compare "rented" to "confused" and "bored"
 "Rented" can't be modified by "very", but "confused/bored" can: we can say "a very confused/bored child", ...
Something that happens unexpectedly could be either pleasant or unpleasant.
If something happens with bad timing, it comes at a time when it causes the maximum distress or inconvenience. For instance, I had been waiting all summer for a date to move in to my present house. When a date was finally fixed, it was the day I was due to go on holiday! (I packed ...
It means nomenclature in this context, but the author seems to be interested in a slightly broader context. Without further reading it is unclear if they mean unfair.
However "constrain our understanding" is often a way to describe the way in which categorization often fails to capture what in most fields is actually a spectrum or graduated scale.
The gerund (-ing) lets a verb function as a noun. "Resolving the problem can be very challenging due to the expensive iterations of the algorithm." sounds natural, as does "Finding the solution to the problem ...".
Your example is fine as written. Imagine the following exchange:
You have lots of clothes you can wear to the party, right?
No, the only thing I can wear is my shoes.
In your example, the singular verb "is" agrees with the singular subject "the only thing..." (the verb agrees with the subject, not the complement).
The complement "...
A proper noun has a name, and the name is capitalised when referring to that thing (or person) by its name.
A common noun is not a name, and a capital letter is not used.
Thus "my car" refers to a particular car, yes, but not by its name. You might have a VW Beetle and refer to "my Herbie" because Herbie is the name [proper, capitalised] ...
The reason is that the car, the hat and the dinner in your examples are specific only when the person or people referenced by the possessive pronouns are known. Not only that but when the pronouns reference other people the phrases reference other cars, hats and dinners.
For instance if you say "That is my car" then the phrase will refer to the car ...
Because you are introduced to things and people identified by nouns, not by verbs.
You might be introduced to snails for example, or to Professor Mollusc the great expert on snails, or to research on snails, or to doing research on snails. However you would not be introduced to do research on snails unless you were being given a job with Professor Mollusc, ...
'Squits' is a similar term commonly used in colloquial British English for diarrhoea. This meaning of the word is found in British dictionaries (Oxford, Collins, etc), but not in Merriam-Webster, so I guess it's not a common term in the US.