As Masusta or Wikipedia states: mast, maazuza, masustra, masusa, masurta, ma(t)zusta, masosta, marzusta, marzuza, martutza, marzoza, marzoza, matsutsa, matsuts, matxinch, matust, mast, mast, machuja, mast.
You know that what is from here to back is my mere opinion. It seems to me that the word “masusta” indicates a certain type of fruit. A fruit shaped like polydrupa, with a nutrient that contains many grains with drupa or a bone inside.
The mulberries are produced by plants of two genera: Rubus and Morus. Laharra (especially Rubus ulmifolius) and mugurdiondo (Rubus idaeus) belong to the genus Rubus. The bush fruit is called walnuts, the raspberry rainbow, two red also walnuts, sharps, pints, red, marcillosas, painted... Fresa (Fragaria vesca) is also known as painting, painting, magu, hose, hammer, hammer, spider and joint; the plant is also called painting. Blonde trees are bushes, strawberries are herbaceous, all perennials.
The Morus genus is the muzzle of the other sidran. They're trees, I call them "marugar." There are many, two of the best known: the white marugado (Morus alba) and the black marugado (Morus nigra). Morus's name comes from Latin, in this language it's called "marugada." The marugado is also known as masusta, masuster, masustondo, masusta arbola, masusta tree, moraondo, martolzaondo, marzokaondo, martutz-piku, martutzondo, martotsondo martxuka, marukaondo, marusta-habe, masustabe, parra, etc. The fruit of the marugado is the maruga, but also a luuco of martola, martoltza, martutz, martxuka, etc.
Is it in part the fact that it was developed together with Spanish that brought this mixture to us? They call “mora” to the grain of the zarzamora rather than “zarzamora”, and that of the butterfly. We bite both of us. We also know with the same names similar fruits, that way or similar to those mentioned above. And most names start with ma. The marua is a stain, the trace left by Moscow or the muskrat of the nut grain; that is, the maruca. Ma, ma, ma...
You have to go crazy at this naming party. I've been crazy about these things for a long time, but I guess we'll have to do something to understand ourselves. Because it takes courage and energy to live in this mess. Marugar, maruga is for the tree and zarzamarra for ivory. Indeed, it was a moral duty to myself. In Spanish it is thus said to the mastication: “moral”.