A dynamic architecture is one that focuses on speed. There are two parts to this. 

Firstly, there is the content portion that refers to the architecture as a product: The form of the architecture is such that modifications to new, as yet unforeseen, developments are as rapid and inexpensive as possible. The architecture can support changes in the business operations swiftly. 
Disconnect points; getting data at the source; guidance with interfaces and separation of the presentation, business and data layers. 

Secondly there is the process side: dealing with architecture. This relates to the design and support of the architecture is dynamic. The organization manages the phenomenon architecture in a smart, streamlined and swift manner. Matters such as multidisciplinary collaboration, just in time architecture and the project start architecture play a role.