[bayindirh]

I used the term "dark" as in unshared, and as a result, you use it the way you like it.

Also, the term looks like it has both meanings.

Having a "dark fiber infrastructure" means having a web of unconnected fiber cables point to point, but since you connect your own devices to it, you don't have to share it with others.

As a result, its presence and its state is only known to you (i.e. it's in the dark).

I understand that my usage is not completely true, but in that context, it's not a flat-out blatant mistake either.

[rincebrain]

It's also not uncommon - people often describe big tech using dedicated lines they didn't lease from people as "dark fiber".

[FroshKiller]

I understand better now, you are really applying "dark" to the infrastructure (which happens to have fiber-optic cable) rather than to the fiber itself. The infrastructure is figuratively dark, and the fiber is literally lit.