Scalable & Robust - Definition

Scalable - In telecommunications and software engineering, scalability indicates the capability of a system to increase total throughput under an increased load when resources (typically hardware) are added.

Robust - In computing terms, robustness is reliability or being available seven days a week, twenty-four hours a day. Robustness is an important characteristic of the internet because network design is a key factor in the availability of data.

It means the ability to keep running when unexpected events (which can cause Exceptions) occur.

"able to survive partial failure"

I also like to talk about robust design, able to survive fundamental unexpected changes in requirements and technologies.