If Xenoblade DE is remaster only, Nintendo would have called it Xenoblade HD. Rememeber Wind Waker HD and Twilight Princess HD?

These terms come from the music industry.  "Remaster" means make a new master copy in a higher quality format.  "Remake" would mean to create the song again usually with different artists and a different take on it.  For example, we could say that Disturbed remade Sound of Silence with their own take on the song.  It is the same song as the Simon and Garfunkel original, and yet they made it their own.  The song is different on an artistic level and not just a technical level.

Likewise George Lucas has remastered the original Star Wars trilogy plenty of times.  Mostly the changes are on a technical level, although a few changes are on an artistic level (like who shot first).  Generally when fans want a remaster they don't want any artistic changes, just technical changes.  On the other hand the movie "A Star is Born" has been remade many times.  A basic outline of the movie looks similar, but the details can be extremely different.  So the recent version with Lady Gaga and Bradley Cooper is similar enough to resemble earlier versions of the movie, but in looking at the details there are significant (artistic) differences in how the movie plays out each time.  It's not just about changing the technical quality of the film or special effects.

So, when we get to video games, I believe the terms "remake" or "remaster" are somewhat subject to interpretation, and marketing can play a misleading role depending on how a company wants to portray a game.  But generally a game which only has technical improvements (like graphics) will be received one way, while a game with changes to artistic elements like gameplay, story, controls, level design, etc... will be received another.  So, I believe it is best to use the term "remaster" to refer to a game with mostly just technical improvements, while a game with significant artistic changes should be called a "remake".  And as I've said above this is how the terms are used in other industries.

Examples

Remaster:  Super Mario Bros (8-Bit) -> Super Mario All Stars (16-Bit), uses a different graphics engine, but has identical gameplay
Remake: Metroid -> Metroid Zero Mission, changes not only to graphics, but controls, level design, some power ups, monsters, etc... but has lots of similarities too.

He has already answered you. It's a marketing move. Crash fans would have badly overreacted if the game was called Crash Bandicoot Trilogy Remake, because "Oh no they're ruining my favourite game!". By calling it a remaster people would have understood that the game was not ruining the original one. But this is something that has already been written, you have basically just ignored it and prentended he has no arguments. Let's talk about Panzer Dragoon Remake: it should be easy for you to look on youtube and see original game walkthrough/gameplay, then look at the "remake" footage, developer called it a Remake but it's clearly not. Now let me say something: FFVII is a Remake but in a different way than Xenoblade Chronicles Defintive Edition is or Crash Bandicoot N.Sane Trilogy, Crash Team Racing Nitro Fueled or Spyro Reignited Trilogy. I'd like to call those game as "1:1 Remake" to separate remakes like FFVII Remake or RE2/RE3 Remake from those remakes that are made from scratch but they're basically the same as the original ones

Oh, really? When did that happen?

Was it when you guys called a game remake despite being called remaster in the box art? Was it when I brought to you the case of Kingdom Hearts HD were it had be pretty much recreated again but it is clearly a remaster, but you just decided to ignore it? Or was it when you guys said FF VII Remakes was not a remake (lol)? Oh, wait, maybe it was that time you guys tried to justify Xenoblade DE being a remaster by bringing up a comparison video where it was clear as day that it was the same core skeleton, with the same shots, the same movement for the characters, the same FUCKING EVERYTHING... but with better textures and lightning? Wait, wait, wait... I have this one... It had to be that time I wrote for you definitions for remastering, remaking and rebooting with examples and you guys IGNORE IT AGAIN BECAUSE YOU HAD NOTHING ON IT.

Which one was it, Blake? Get real, the only time you or anyone on this thread proved me wrong on this specific topic was in your dreams. So keep dreaming if it makes you happy. But Xenoblade Chronicles Definitive Edition will still be a port of the original Wii game where they changed the original textures for prettier ones and gave everything a better lightning. They did not open a game engine and started an entirely new project. The took Xenoblade (Wii) and proceed to remove and add things. End of the story.

So... instead of just admiting the developers called the game what it actually is, you are are going to imagine what the players might have thought of said name and also going to assume that the developers shared your imaginary idea and decided to lie and call the remaster a remake. Wow you guys are really trying really hard to have a point xD

You know nothing about programming and modeling. Illumination, shaders and assets we have seen in Xenoblade DE are impossible to create in the older engine, they may have re-used older rigs and older map (which I'm pretty sure they did), but it's clearly made on a new engine and that's enough to call it a remake, but not like FFVII, just a 1:1 Remake.

Port: The same game (and engine) with improved resolution, image quality and better framerate (often with no improvements though), maybe new content. Examples: Mario Kart 8 Deluxe, The Witcher 3 on Switch, Ni No Kuni on Switch (PS4 and XboxOne versions are remastered)

Remaster: The same game and engine (=exact same code) with more stuff improved, like redefined models (same models but improved), better image quality, resolution and framerate, a more polished game, but it's the same game as the original, the code is basically the same. Examples: Ni No Kuni Remastered (PS4 and XboxOne versions), FFVIII Remastered, DMC HD Collection, GTAV on PS4 and XboxOne (though this one could be defined as an "Enhanced port"), The Last of Us Remastered

Remake: The game is made from scratch, maybe some parts of the code are reused but the game in its majority is new. Completely new models, new engine, often new rigs, new illumination, shaders and assets. Examples: Pokemon LeafGreen/FireRed|HeartGold/SoulSilver|AlphaRuby/OmegaZapphire|Let's Go Pikachu/Eevee, Crash Bandicoot N.Sane Trilogy, Crash Team Racing Nitro Fueled, Spyro Reignited Trilogy, Super Mario 64 DS, Ocarina of Time 3D, Majora's Mask 3D, FFVII Remake, RE2 and RE3 Remakes, Metroid Samus Returns, Link's Awakening, Shadow of the Colossus adn Xenoblade Chronicles Definitive Edition. A lot of game of this list are 1:1 Remake, others are "more free"

Reboot: IP restarted, basically this lol. Same concept and maybe main characters, but different story and they have nothing to share with originale games. Examples: Doom (2016), Prey (2017), Tomb Raider (2013)

A Remake is not only like you said "made from scratch, the same game but at the same time different product", it's also this but not only, Like I said before i'd like to use the definition of 1:1 Remake because this is how CBNST, CTR, SRT, LA, SotC and Xeno DE are made, differently from FFVII Remake, RE2 and RE3 remakes are made

I mean, It wouldn't be the first time in the game industry

Anyway... I took a looked at a comparison between the original Panzer Dragoon and the Remake:

And while there is certainly a lot in common between the two, there's clearly a certain degree of liberty that was taken in the remake. It's not about the graphics: the way the cinematics are shoted, the way the levels are designed and how the movement and logic of the game works is definetely not a 1:1 copy like a remaster would be. It's clearly a new take on Panzer Dragon. Much like other remakes like Metroid Zero Mission... is the same, yet a different thing.

Now let's take a look at a comparison between XC (Wii) and XC DE:

1) We inmediately can see the difference between this and Panzer Dragoon. 2) This is clear as day, a 100% carbon copy of the original Xenoblade Chronicles. They just changed the textures for high quality ones and throw in there a new lightning solution. But it has not been recreated in any way or form, nor it does anything different from the original. Because it is a remaster.

3) There is no such thing as "1:1 remakes". A remake in any kind of media product (like a movie or a song) implies a certain degree of departure from the original source. Which Xenoblade Definitive Edition does not have.