Taxonomy is the science of defining groups of biological organisms on the basis of shared characteristics and giving names to those groups. Organisms are grouped together into taxa (singular: taxon) and these groups are given a taxonomic rank; groups of a given rank can be aggregated to form a super group of lower rank, thus creating a taxonomic hierarchy. (From Wikipedia)
Names are important. We humans, when we encounter some strange new item, the name of which we don't know, find it difficult even to think about this item, let alone talk to others about it. So, it is built into our human nature to give it a name, often based only on its appearance.
This accounts for names like 'pond apple', 'bell apple', 'cocky apple', 'black apple', 'Sodom Apple', and many other 'apples', for fruits that are not even related to apples. In the next town or country, people might give this same item yet a different name. Marketers often dream up fanciful new names in the hopes of selling more fruit. The result is great confusion. As a group devoted to all aspects of fruit-growing, we need to use correct binomial names wherever we can.
This problem of correct identification of plants and animals was recognised long ago, and the best solution that evolved after many discussions and arguments, was the binomial naming system, applied to both the plant and animal kingdoms.
The word 'binomial' is derived from Latin and means 'two names'. To put it simply, a plant (or animal) is given a first name in Latin, the genus or the 'specific descriptor,' which is written with an initial uppercase letter and is usually descriptive of physical characteristics or the name of the plant in a local language. The second name, the species, can be derived from its appearance, or who discovered it, or the place where it originates, or some other characteristic. The second name is written with all lowercase letters. Both the first and second names are written in italics, to distinguish them as a binomial name. There can also be a third name which usually indicates a named variety, and which is not written with italics. There are many websites that offer more thorough information about the history and development of this system.
So, does this solve all our problems about getting the correct name? Sadly, no. There is a committee at work that vets binomial names, and as plants are discovered or investigated more thoroughly and with modern technologies, it can become obvious that a particular plant may have been incorrectly categorised. So, the committee then recategorises and issues a new name (and disrupts quite a few other people). Occasionally, new names are proposed by influential establishments, like Kew Gardens, or groups of academics publishing in an appropriate journal.That is why you may see explanations that give the new name with notation that this plant was formerly named something else. Some plants have undergone multiple changes of official names, spanning centuries. Mature classifications lead to better understanding of how plants are made up, helping us to breed better plants and crops, best management methods, what can be cross-grafted, and so on. (And you better believe that the arguments in the committee and among academics about names and classifications can be hot!)
Wikipedia has a helpful database of Latin and Greek words common to binomial names:
As you use correct binomial names, you will begin to recognise the Latinised words. You soon will recognise names such as 'alba', which means 'white', and 'edulis', 'edible', and so on.