Re: Can we see that aikido is all over the place in MMA?
A definition and a description are not the same thing, Ron. I wish there were a nice way to say this, but you're just wrong. Something that is defined one way can be described many ways.
Let's use your apple example. An apple is the fruit of the Malus domestica, or apple tree. Different people can describe an apple different ways (red, green, tart, sweet, crispy, etc.) according to how they experience it, but none of those descriptions change--or indeed impact in any way--the definition of apple. No matter what the description, the definition remains the same: an apple, by definition, is the fruit of the Malus domestica tree.
Your argument is that something which can be described many ways cannot have a single definition, because every description serves as a new definition, and that is demonstrably false.
Now back to OP. Say we define aikido as a martial art originating with Morihei Ueshiba, whose technical curriculum is derived primarily from Sokaku Takeda's Daito-ryu aiki-jujutsu and which is intended to explore and express the physical and spiritual principle of aiki. By giving aikido such a definition, we create word that (a) means something specific in conversation, (b) functions as a name for our particular martial art, (c) acknowledges that our art is about something bigger and more important than a particular set of techniques, and (d) makes no judgement about which individual style is the "true" art. It does everything we need it to do, and no one else in this thread has provided a definition that accomplishes that (except maybe Cliff and Andy, whose definitions are very similar to mine). What such a definition does not do is allow us to say that we see aikido "all over the place in MMA". It would be far more correct and far less obfuscatory to say that we see the principles of aikido or the lessons of aikido "all over the place in MMA".