Long live the compound noun!
Well I might be exaggerating a bit, but in to the sixth edition of the Shorter Oxford English Dictionary hyphens have been removed from around of 16,000 words, many of them two-word compound nouns.
For example:-
Fig leaf
Hobby horse
Ice cream!
Pin money
Pot belly
Test tube
Others have become one word:-
Bumblebee
Chickpea
Crybaby
Leapfrog
Logjam
One word that is causing a bit of a problem is the word e-mail. To hyphenate or not to hyphenate, that is the question. But at the risk of looking old-fashioned I will continue to write e-mail. That way I can avoid the confusion with the German / French word email, which means enamel.