The Vocabulary of Exploration
I often discover the words that describe the things I'm designing or studying long after I've actually gone ahead with them. There is so much information available to us that we have a habit of assuming that there isn't an easy answer for so many of the things we do. Inevitably, there is.
Vocabulary is an excellent source of insight into finding these easy answers. Knowing the words that experts use to define and categorize the subject you're assessing will put you immensely closer to the answers you need to understand them. Books, too, provide these sorts of answers in abundance. To keep it brief and get to the examples, know only that it is incredibly important that you take note of such keywords as you explore the world through your art.
Below are a series of individual terms or resources that will help you (by which I mean "me") find a foothold for breaking down the universe into categories that can be more readily filtered through these human brain things. These are by no means definitive, they're more examples of terminology collections and resources.
Greebles - You know all those meaningless details plastered over the surfaces of space ships in film and games? Those sorts of details are called "greebles", "nurnies", and "wiggets". These concepts are now tied to procedural generation of content for filling space.
Drapery - Trying to decipher the myriad of crumpling, rippling, stretching folds across a shirt is hard. Trying to imitate such patterns without reference on a design of your own is darn near impossible without some mental picture of what's going on.
Architecture - .
Hair Styles - .Obvious as it may sound, if you struggle to come up with hair styles, consider looking through a database of styles from a fashion dedicated website. You'll get the normal dos, the abnormal dos, and the what-in-the-world-is-that dos. What's more, you'll learn some of the words used to describe hair styles by type (pixie, bob, fringed, classic, whatever).
Clothing Styles - Finding outfits for your characters and creations can be quite tough for those of us without a native fashion module in our memories.
Human Heritages - As an artist, it's sometimes important to be able to depict the genetic heritage of your character or, more importantly, to free yourself of the similar faces that you see around you. If you're looking to trace the history of your character through the facial characteristics of some part of the world, consider Majnouna's broad exploration of the subject. Rooting their studies in the populations of the recent past, they use "ethnotypes" to loosely divide the world into genetic heritages. They present a rambling example of how to describe what is unique about a face as well as a few of the words that may help you explore them further. The resource actually helps glue my geographic and historical understanding of the world together and gives me a handful of helpful color terms for describing skin, hair, and eye colors.
As with any anthropological resource, be aware that such data is fleeting and incomplete. There is no such thing as "always" when it comes to your designs, yet it's equally important to recognize the visual combinations which produce the diversity that describes our species. The value of this particular resource is that it's provided such a great deal of helpful, basic, and unassuming information that you'll easily be able to apply it to your own needs.
Landforms - Trying to design a living breathing world is so much more interesting if you can describe the bizarre varieties which we observe even on our own planet. Exploring the ways in which these landforms are created can further provide reasoning behind your design choices. "The Teacher from the Black Lagoon" is more interesting for having dredged up the word "lagoon" rather than "swamp". Even the words we recognize--fjord, bight, sound, bayou, strait, cape, gully, etc.--we may not know quite how to put them to use. Even remembering that such words exist makes an enormous difference when trying to design and research your landscapes.
Animal Anatomy - As is the case with human anatomy, many of the most well known masters are from the recent past. Ellenburger's "An Atlas of Animal Anatomy" and Elliot Goldfinger's "Animal Anatomy for Artists" are the two whose books have been most recommended to me and which I've personally appreciated. Ellenburger's work can be found online, too.
Combat Positions - .
Arms and Armor - .
Horse Anatomy - (Gait) (Tack) (Bones) (Anatomy)
Human Anatomy - .
Plant Anatomy - .
Historical Furniture - .
Historical Clothing Terms - .