[qume]

The article isn't the canonical source of the meaning of the word pure. And yes, the word pure _literally_ means 100%

My point was that the author has misused the word pure. Which remains my point as your argument has failed to add anything valid to change this.

[acqq]

> the word pure _literally_ means 100%

Only to you, if you observe it out of the context. The practice is completely different, and the OP article wasn't incorrect.

http://www.thequartzcorp.com/en/applications/silicon-metal.h...

"For silicon metal to be used in solar and semiconductor applications it must be extremely pure. For solar applications, the metal must be 99.9999% Si, while semiconductor applications require 99.999999999% purity. No quartz product can be purified above 99.999% SiO2, which means silicon metal must go through successive purification processes before it can be used."

As you see, the common use in the industry of "pure" is somewhat as "went through the process of the purification," therefore if it is purified more than what is commonly referred to as "pure" then it's "extremely pure" or can even be called "ultra pure" (edit: note, in the sense of "purer than what is typically offered as pure" and not in the sense of "more than what anyway doesn't exist").

In practice, anything "completely" purified, so that "not even single atom of the impurity remains" simply doesn't exist. There's no absolute, only different achieved levels of what is commonly called "pure": See e.g. "Purest silicon sphere ever created":

https://www.chemistryworld.com/news/purest-silicon-sphere-ev...

The common usage, that you object to, reflects the reality.