Streamlining reduces drag — the friction that slows a system without contributing to its output. The term comes from fluid dynamics: a streamlined shape moves through a medium with less resistance by eliminating surface irregularities that create turbulence.

Streamlining work removes overhead, reduces latency, or increases throughput without changing what the system does. It is distinguished from margin (which adds capacity) and harden (which adds protection) in that it removes cost rather than adding buffer.