Solution:
A Solution describes the implementation of an Architecture, by defining reusable building blocks.
Four solution categories:
- Product & Services
- Systems Solutions
- Industry Solutions
- Enterprise Solution

see http://en.wikipedia.org/wiki/TOGAF#Enterprise_Continuum
see http://www.opengroup.org/architecture/togaf8-doc/arch/chap18.html#tag_19

"Architecture":
An Architecture specifies the structuring of reusable architecture assets, and includes rules, representations and relationships of the information system(s) available to the enterprise.
see http://en.wikipedia.org/wiki/TOGAF#Enterprise_Continuum

ANSI/IEEE Standard 1471-2000
Specification of architecture: "the fundamental organization of a system, embodied in its components, their relationships to each other and the environment, and the principles governing its design and evolution."

TOGAF:
Architecture is a "formal description of a system, or a detailed plan of the system at component level to guide its implementation", or as "the structure of components, their interrelationships, and the principles and guidelines governing their design and evolution over time."

http://www.opengroup.org/architecture/0404brus/papers/rakesh/abb-1.pdf:
Building blocks extend the concept of a framework to architect in IT environment. A building block approach helps categorize the components of building an IT architecture into hard, soft, and connector building blocks. Hard building blocks are a combination of software and hardware, which can further be divided into systemic and application tier building blocks. Soft building blocks are software entities like Enterprise Java Beans (EJBs). Connector building blocks are the glue that connects all the components. Building blocks and architectures using building blocks might use one or more architecture patterns.

Enterprise Continuum
This is an important aid to communication and understanding, both within individual enterprises, and between customer enterprises and vendor organizations. Without an understanding of "where in the continuum you are", people discussing architecture can often talk at cross purposes because they are referencing different points in the continuum at the same time, without realizing it.
Quote: "Not only does the Enterprise Continuum represent an aid to communication, it represents an aid to organizing re-usable architecture and solution assets."
see http://www.opengroup.org/architecture/togaf8-doc/arch/chap17.html
see http://www.opengroup.org/architecture/togaf8-doc/arch/chap18.html#tag_19

References:
http://en.wikipedia.org/wiki/TOGAF.
http://www.opengroup.org/architecture/0404brus/papers/rakesh/abb-1.pdf
http://www.sun.com/products-n-solutions/sodc/SODCwp.pdf
http://www.opengroup.org/architecture/togaf8-doc/arch/toc.html
http://www.opengroup.org/architecture/togaf8-doc/arch/chap18.html#tag_19