Let's list what we have so far:

compound words (e.g., mountain lion, riding boot, arctic fox or Arctic fox, depending upon your dictionary)

collocated terms (e.g., crystal clear, kick the bucket, and nuclear family)

irreversible binomials (e.g., ham and eggs, love and marriage, agony and ecstasy)

dvandva or copulative compounds (e.g., pair, newlyweds (?--would plurality discount this one), maybe trio and similar words, unless the members need to be more distinct)

bahuvrihi or possessive compounds (e.g., high-fiber).

Can you give us some other examples of these last two compounds so we can detect a pattern? Do the possessive compounds have to be hyphenated, for example? Since the copulative compound is a simple word, such as pair, could the possessive compound also be a simple word such as bushel?

I'm trying to find a good article online, but haven't found one yet.