Q. I’m having trouble explaining to my organization why “the internet” is now lowercase “i.” We do follow CMOS style, but the Internet Society and some others are insisting otherwise. Can I get an explanation that I can use? Not seeing any in the manual.
A. An explanation is beyond the scope of CMOS, but here’s a summary: In ordinary usage, internet with a lowercase i has been common since at least the introduction of the iPod (in 2001; note that lowercase i). And because ordinary usage tends to determine how tech-related neologisms are styled, many guides now prefer lowercase internet—including not only CMOS but also the latest from Microsoft and Apple (computer tech), AP (journalism), APA (psychology), and AMA (medicine).
Meanwhile, documents published by W3C and related organizations that develop or maintain the standards that determine how it all works still tend to refer to the Internet when they mean the worldwide network of computers (but internet when referring to any interconnected network). And as recently as 2019, Internet was still more common in published books than internet—though the trend toward lowercase is clear.
So the usage preferred by specialists may be less common than it once was, but it’s far from defunct. And according to CMOS 7.2, any discipline-specific preference (which would extend to capitalization) should be respected.
All of which is to say that if you’re editing for the Internet Society, which is in the same league as W3C, then you should accept the capital I. For most other types of organizations, common usage will likely be the better choice.