Living in a culture that seems to prefer initials over actual words, we usually see this concept written as HD, as in HDTV for High Definition TV.
So what is meant by High-Definition, or Hi-Def for short?
It’s simply a way of differentiating the number of pixels from what would be considered low to high. Low-Def means fewer pixels, and hi-def means more pixels. More than what? Well, that’s the rub: “Hi-Def” is, by definition (no pun intended) a relative term, lacking the precision inherent in other terms that measure resolution (e.g., 4K, 8K, etc). It can mean several different things.
Usually, Hi-Def refers to a resolution of either 720 pixels (translation: really low-end TVs) or 1080 pixels (translation: more standard TVs). Either of those counts as Hi-Def. Of course, you may be wondering why you would settle for what I am calling Hi-Def when you can get a 4K TV that is significantly sharper in resolution.
Two reasons come to mind: price and noticeability. Hi-Def TVs, as of this writing, as significantly less expensive, so if your budget is tight, go with Hi-Def. Likewise, if you are not too picky about the resolution of the picture on the TV screen, or if your eyesight is somewhat compromised (as we are all getting older), then it may not bother you to have a Hi-Def TV.
But if money is no object, and if you are one of those people that demands the latest and greatest, you may want to compare Hi-Def with 4K when you are out shopping for your next TV and see if the price differential is worth the picture quality. It may well be worth it to you.
Bear in mind that everything I am saying right now in my comparison of Hi-Def TVs and 4K TVs will soon be said in the same exact way for 4K TVs and 8K TVs. And the pattern will probably continue into the foreseeable future, with the discussion one day comparing 8K TVs to 16K TVs, then 16K TVs to 32K TVs, etc. Try to imagine the time in the future when we are discussing 64K TVs! Now that will be something!