Some decades ago, back when I was spending a lot of time learning to ID plants (and other things), it was interesting to learn about the multiple common names for them. One general rule that I was introduced to is that the more popular a plant is — usually meaning it provides something good to eat! — the more common names it will have. This also was related to how wide spread the plant is, the larger the range and the better the fruit, the more common names a plant will have. Along with this, the same common name is often used for different plants (fruits, berries) in different areas. Then there are also English common names and Native American (derived) common names, and the Native American names followed the "rule" of things that were more popular having more names that varied by area.
THIS is why standard system of scientific names, known as binomial nomenclature, was developed by Carl Linaeus — each species is given a unique, two-word name: a capitalized genus name followed by a lowercase species name. This way there would be a single standard way of consistently designating every single living thing on the planet, no mater where one might find it. This made everything so much simpler for everyone .... until multiple names started being used for some (many) living things.
Sometimes, back in the olden days, communication wasn't fast enough or reliable enough to spread the first binomial designation far and wide, so someone else would come up with a different name for something that had already been named by someone. Sometimes something was classified as a particular genus, but later reclassified to some different genus, so the name was changed to reflect better knowledge and understanding. Sometimes something thought to be a single species has been found to actually be two distinct species, other times what was thought to be two species has turned out to only be one species. Further complications have arisen when the official distinctive descriptions for a genus or species has changed as more has been learned about known examples, often through testing DNA. Sometimes the species name was in honor of someone special, often the first person to "discover" or classify it, but then it might be realized that someone else should have gotten that honor so the name was updated. Sometimes the "experts" would disagree about what the name (genus or species) should be and two names would have to compete for acceptance. There might be some other complicating reasons that I'm not remembering at this moment. In theory, the binomial naming system was perfect. In practice, the system quickly got messy. There are many plants and animals that ended up with multiple "standard" names over time — sometimes two or three, other times maybe half a dozen or so. There is supposed to be an "ultimate authority" (society or organization or whatever) that is supposed to 'finally' decide on the 'real' and 'correct' name, but even that is a less than perfect system. So, the more academic texts will list multiple scientific names for various entries, a practice that is necessary for historical references back to prior publications that used the "correct" names of the times that later got "corrected" to "better" names that were officially accepted and approved.
As genetic testing has developed and its use has been greatly expanded, and as thinking about how best to describe and assign evolutionary relationships between various species, there have been various proposals put forth to basically replace the original Linaeus naming system with something that will help better depict the actual evolution of all the species — rather than the observational structural analysis of body parts and function system that the old names reflect.
Living things aren't the only ones with complex and complicated and less than perfect naming systems. Rocks and minerals also can have different names. The complication here is that rocks especially, and sometimes minerals, can vary significantly depending upon exactly how they originated, including whether they are igneous, metamorphic or sedimentary, or what the temperature or pressure were and how they changed, or how much water was involved, or how much time transpired. This can affect characteristics such as color, texture, density, hardness, toughness, cleavage, and exact chemical composition. Consequently, minerals – which are theoretically defined according to exact chemical compositions, plus variations! – can have local names based on color, patterns, crystal shapes or styles or forms.
There are also local names for rocks or minerals that are essentially the same except for the fact that they were found in different locations with slightly or dramatically different conditions. Also, rocks and minerals that are commonly used in specific ways and/or are very wide spread and readily available will have more names. Although there are charts that are used to help classify and name rocks, there are different charts for different locations and different purposes. Finally, rocks don't have "official" names as much as they do have local names, although the local names are based on "official" names. Got that!? It's a great example of the more you know the more you don't know – unless you really know, based on the particular situation.
Oh, and rocks that are used architecturally or industrially typically have very different names in their industry use from what a geologist would call them. In fact, rocks used for buildings, counter tops or grave markers are very often knowingly given "incorrect" names. For one local example, "black granite" is quarried just south of Ely along Hwy. #1 but it is actually a gabbroic rock, mostly anorthosite, which is chemically and geologically far from being any sort of granitic rock, yet it is marketed as "black granite."
Congratulations and thanks if you managed to wade through all of that.
Carl Karasti