I see a Raymond Carver reference, and I upvote accordingly.

It bears reminding that “sideload” is a made-up term. Putting software on your computer is simply called “installing”, regardless of whether that computer is in your pocket or on your desk. This could perhaps be further precised as “direct installing”, in case you need to make a distinction between obtaining software the old-fashioned way versus going through a rent-seeking intermediary marketplace like the Google Play Store or the Apple App Store.

Regardless, the term “sideload” was coined to insinuate that there is something dark and sinister about the process, as if the user were making an end-run around safeguards that are designed to keep you protected and secure. But if we reluctantly accept that “sideloading” is a term that has wriggled its way into common parlance, then we should at least use a consistent definition for it. Wikipedia’s summary definition is:

the transfer of apps from web sources that are not vendor-approved

Every time someone claims sideloading isn’t a made up term and has a distinct meaning beyond traditional installation and beyond being non-vendor-approved, I feel like I’m taking crazy pills.