Sorry that page I sent you to didn't really say much about 4+1. I found a fresh link to
Krutchen's paper.
The point I didn't really bring out is that architecture means many different things to different people. Someone who says "architecture" might be interested in
*Whether the app is fat client or web or other
*General architectural
patterns, eg MVC2
*Detailed class designs: how did you do X?
*Technical stack, what products and frameworks are used
*High availability: redundancy, load balancing, failover
*Geographic distribution
*Whether your database is partitioned
*Packaging for reuse or partial deployments
*Performance, volume and throughput
*Network capacity, configuration
*So many more ...
If someone just said "Describe the architecture" I'd probably ask what interests them, maybe list Krutchen's four views to explore the focus of the question. Or run to a whiteboard and draw for three or four hours.