Aura: Only about 25% of Migraineurs experience an aura. An aura can be different things to different sufferers. Visual issues such as flashing lights, floaters, zig zag's, blurry vision or even loss of vision. My friend Rain just found a great video on aura, which you can see HERE.
Abortives: Abortives are medications that actually abort a Migraine attack. There are quite a few options in abortives right now, including Triptans ( Amerge, Axert, Frova, Imitrex, Maxalt, Relpax, Treximet, and Zomig ). Then there is Migranal, DHE, and newly back on the market, Ergomar which are Ergotamines. And last but not least, Midrin, which is a combination of Acetaminophen, Isometheptene, and Dichloralphenazone. Abortives can come in many forms such as pill, capsule, indictable, IV therapy, nose spray, and even wafers. Not all abortives are available in each form, click the links for more info on them.
Alice in Wonderland Syndrome: Given the name because of famous Migraineur Lewis Carroll's book, Alice and Wonderland. This is a specific type of aura that can make a person feel like they are too big or too small. Teri Robert just recently wrote a great article on this: Alice in Wonderland Syndrome: The Basics.
Aphasia: The inability to speak or trouble speaking. Also may affect comprehension of words.
ADVOCACY!!!!!: Teri Robert, the top Migraine Advocate! Advocacy is empowering yourself, sticking up for yourself, and teaching others to do the same. It's fighting for a cause. It's busting your butt, it's having a great passion for something. This is how I view the word Advocacy.
Wow - "A" is a big one! I didn't do them all, because you would lose interest in reading them, and I also wanted to give you, the readers a chance to add your own! Please feel free to add any other "A" words you feel fit in with Migraine, and give a definition.