The Audible Frequency Range
If you play through an amp with treble, middle and bass controls, you can experiment with the extremes of each control setting to get a feel for how the relative level of each frequency range shapes the overall sound. "Scoop the mids" by turning the middle control down. "Roll-off the lows" and "thin-out" the tone by turning down the bass control. Now, "Fatten-up" the tone by turning the bass control back up.
First, there are the basic tonal adjectives that stand on their own. Most guitarists would understand their meaning without the need for much clarification. The words in this group stand on their own because they are closely related to common control settings. Describing tone is simplified considerably when a comparison can be made and most of the adjectives in this group can be paired with a clear opposite. For example, you might compare bright vs. dark for highs, full vs. scooped for mids, fat vs. thin for lows or some other variation to express more or less of a particular attribute. You could say, "I'm using Acme brand 12AX7 tubes in my amp and they sound too muddy, I need something that will brighten up the highs and give me more gain."
Second, there are the ambiguous adjectives that leave you with some doubt as to what they really mean. They serve as a kind of garnish to add personality and make a tonal description sound more appealing or marketable. For example, the highs might be crisp or bell-like with sparkle or chime, the mids might be buttery or woody, there might be mid-range honk, the tone could be warm, rich or creamy. This is good stuff if you don't take it too seriously, but these words don't really mean much on their own. If someone told you that a particular speaker sounds "rich and creamy with buttery mids and crisp highs," they might as well have said, "it sounds great, trust me." Another aspect of this group of adjectives is that they can allow you to identify a target audience that the product was designed to reach. For example, you probably wouldn't target the death metal crowd with a "warm, vintage-voiced pickup with rich fat lows and top-end sparkle to express the subtleties of your playing style in fine detail." You'd be more likely to describe "fat, thunderous lows with upper mid-range sizzle and crisp highs for brutal rhythm and scorching leads."
When communicating with other people to get suggestions for which product might get you closer to the sound you're looking for, it's usually best to make comparisons, while using mostly adjectives from the first group and going light on those from the second. Of course, the best way to know if something is right for your sound is to play through it yourself and set up an A/B comparison, but that's just not always possible. So as we journey along in our pursuit of tone, we have to develop a vocabulary to help ourselves and others find the way.