Do bear in mind that it is not only the name that is being registered, but rather, there is also a logo in addition to notched X, accompanied by a smaller 5 to go along with it to boot. The LG X series at the moment comprises of the X cam and the X screen models, where these two handsets do seem to have placed themselves comfortably within the mid-range market.
Apart from that, the LG G5 SE is also in existence, being a souped down version of the LG G5 in selected markets, and hence we can only speculate as to what the LG X5 is going to be when and if it hits the market eventually.