Fractionated coconut oil simply means a coconut oil that has gone through a complex industrial process that involves fractional (or steam) distillation. Some people say that a fraction of coconut oil is extracted and so it is called fractionated coconut oil. You can put it that way too, but a more appropriate way to explain the meaning of fractionated coconut oil is its association with fractional distillation or simply fractionation.
But you must know that fractionated coconut oil is actually not exactly coconut oil because its pure content of caprylic and capric acids can also be obtained from palm kernel oil or goat milk (I think this goat milk thing won't happen since it would be too costly to extract caprylic and capric acids from it).
Manufacturing companies name it fractionated coconut oil probably because coconut oil's massive health benefits have been established in the past several years and are going on strong even now and will definitely continue to spread like wild fire.
So, adding the words "coconut oil" gives a perception that fractionated coconut oil is as healthy as the natural coconut oil everybody is talking about.
Of course, they may think that since they extract the components (caprylic and capric acids) from the natural coconut oil, so it is "legit" to call it fractionated coconut oil.
The thing is, some companies make fractionated coconut oil out of palm kernel oil but yet they still use the name "fractionated coconut oil" just because palm is a very close relative of coconut.
Anyway, just know that fractionated coconut oil does not really mean it comes from coconut or coconut oil. Or even if it does use natural coconut oil in the process of making, the composition of fractionated coconut oil makes it far from being called coconut oil.