(noun) a volcanic rock consisting of angular blocks of lava with a very rough surface
Use "aa" in a sentence
"Well, in Norwegian aa - å, and is sorted last, while in English aa are just double a and comes before ab."
"The three companies of the 16th Battalion camped in aa triangular formation with battalion headquarters located in the center and approximately 10 minutes 'walk from each company."
"Worse, with more than two copies of some genes, each as likely as the next to have SNPs, some of those no doubt resulting in aa substitutions, a few of which may present alternative binding functionality in configurative operation, any or all modifiable post-translation, each coordinated with potentially operative expression suites with a number of other genes with other forms and functions, it doesn't look much like we'll ever be able to pin all THAT down either."