Military grade

There are specific MIL STANDARDS for many things for many different reasons. You would have to read the particular standard for whatever cables you have in mind. Undoubtedly some cables are specified to be able to withstand temperature extremes, salt, water, shock, etc. but other cables might not be specified that way, but some other way. Depends on application. Also undoubtedly, military specifications for cables would not (rpt not) address sound quality per se, in audiophile terms.

Here's an example of a military grade connector:
https://www.adorama.com/sw3502.html?gclid=CjwKCAjwpKveBRAwEiwAo4Pqm63e7zGPSMbX6vH8QILdAdXh2JLdD62c0P1jsv3cCub-H2VayQaFUBoCbJoQAvD_BwE
 - same fancy things used in aircraft. I should buy a box and sell them here at a 50x markup.

A United States defense standard, often called a military standard, "MIL-STD", "MIL-SPEC", or (informally) "MilSpecs", is used to help achieve standardization objectives by the U.S. Department of Defense.

All they're looking for is compatibility with existing equipment and structures, something that can be used, reliably, in various scenarios and applications, without failure.

Is it a higher standard than what's out there? It all depends on the application and what you're willing to settle with.

All the best,
Nonoise

Thanks to all of you for your opinions.
Olimpico

@stevecham 

can you imagine the excitement (read audio butterflies) when I found out that an extremely limited supply of wire would be made available from the SR-71 Blackbirds.
 OMG!   Wire conditioned and aligned at Mach 3+ and an altitude of over 80,000 feet.....Combine this wire with your Seawolf deep pressure depressed (oops, meant compressed) wire and there we have it.  A spectrum so vast, sub-bass beyond Nemo on up to the Stratosphere.  Articulation and stability over three times the speed of my hearing...... my heart skipped a beat just thinking about it.