nominal

[Dave Wilton]

> In the coverage of the space shuttle tragedy I've been struck
> by the use
> of 'nominal' as an apparent synonym for 'normal'. A reporter had
> mentioned it as a special usage, and in a press conference NASA people
> spoke of a mission to take a "nominal load of supplies" to the space
> station and later of sensors reading an "off-nominal" event.
>
> Is this usage just a NASAism or does it have broader currency in
> aviation or maybe military usage?

It's NASA/space jargon. I don't know if it has currency outside the space
community (civilian and military), but it's in the OED2, def # 6, from the
1960s. It's from the sense of a minor variance, being within prescribed
parameters or design limits--limits that in many cases don't leave much room
for variance.