What we call "abstract" should maybe especially depend on what photographers show as "abstract photography". Maybe it is relevant, or maybe not, but I have always been fascinated about languages, their evolutions and the role of wise men. In France, we have a the French Academy (L'Académie française), an old institutions founded in the 17th century, which includes forty members, known as the "immortals". It publishes the official dictionary of the French language and is mostly known for its defense of the French as Molière wrote it (unjustified ! But has some elements of truth to it !) It define standards and underline and recall good usages of the French language Contrary to this tradition, in Scandinavia, we have academies too, but their role is mainly to inform on public contemporary use of the languages: how words are spelled, what they mean, how they are pronounced - by those who speak and write it. I would suggest that when we speak about art and photography, we listen to those who make it: the photographers who produce "abstract photography". Take Photonet as a start and go into the "Random Image Generator", under that category "abstract " for example. Or, go to the Critique Photo forum, using the same filter, or Browse top rated photos. You can use other selections and criteria in Photonet searching for "abstracts", if you wish, but you obviously end up with a view on what Photonetters call "abstract photography". You can also go to other sites on internet and search for the same: Take "Artspan.com" for example, still with the filter "photography/abstract", or Absolutearts.com, or Saatchiart.com and you have a wide understanding of what photographers call "abstract". This might not be your own usage of the term abstract, which is maybe more limited, but it is what the term covers by the photographers in question.