What exactly is "exact" (was Clean Singleton Docstrings)

[Lawrence D’Oliveiro]

On Wednesday, July 20, 2016 at 12:07:25 AM UTC+12, Gene Heskett wrote:
> This klystron amplifier, a new one of which was north of $125,000 in the 
> 1970's when I learned about them, is a long tube, around 5 feet long 
> with alternating sections of copper tubeing and ceramic insulators 
> separating the copper sections. Typically 4 ceramic sections, each of 
> which was sealed to a section of copper equiped with contact rings on 
> each end of the copper sections. A tunable box cavity connected the 
> copper sections together, bridging the ceramic spacer, so that when the 
> tube was "dressed" with these cavity's, and lowered into its focusing 
> magnet, (2200 lbs) you could feed about 1 watt of signal into the top 
> cavity...

What is this “watt” of which you speak? How much is that in foot-poundals per second?