I don't think there can be a dictionary definition of JRPG in the same way you could strictly define a car and even the best attempts I think the definition is going to be fuzzy around the edges since it'd be hard to get everyone to agree on a definition of JRPG. Wikipedia's definition while not definitive I think is a good place to start:
a JRPG is defined as a franchise which: (1) is considered a role-playing game by reliable sources and was made in Japan, or (2) made in another country, but otherwise the franchise would be difficult to differentiate from a JRPG due to having common traits found in JRPGs such as: anime/manga character designs, RPG elements, fantasy setting and widely considered as being inspired or influenced by a JRPG
This definition happens to include Genshin Impact, which while being a Chinese made game seems inspired by the Japanese made Legend of Zelda: Breath of the Wild in terms of gameplay with character designs which are undeniably inspired by anime. Granted, and I have no evidence to support this and this may be entirely wrong but I think a bunch of people who just jumped into Genshin Impact don't know the nationality of the developers and assumed from the character designs it was a Japanese made game, until this post and a quick Google search I personally didn't know Genshin Impact wasn't made in Japan, it simply wasn't something I thought about, in the way I don't think many people know the tidbits that Hotline Miami is technically a Swedish game or Life is Strange was made in France.
This highlights though what I think is an underlying problem with a hard definition for JRPGs, perception is key. Going back to that Wikipedia page there's a list of best selling JRPGs which includes the stereotypical JRPGs Final Fantasy, Dragon Quest, Tales of, etc. no one will argue these aren't JRPGs and feature a bunch of features people strongly associate with JRPGs including turn based combat, character designs that draw from these and anime and the like, among other things but that's an awkward position to take because even these games have diverged from a lot of the features people generally associate with JRPGs, Final Fantasy has shifted away from proper turn based combat and has much more real time elements but again no one will argue FFXV isn't a JRPG. The thing is there isn't a any specific criteria a JRPG needs to fulfill to be a JRPG so long as it was made in Japan and is an RPG there's going to be a JRPG that breaks from every possible criteria someone could toss out to define JRPGs, turn based combat is missing from any number of JRPGs (FF, Monster Hunter), fantasy setting (Mother, anything sci-fi), child/teenage protagonists are common but not universal (Yakuza, Dragon's Dogma), anime/Japanese influence (Souls, Kingdom Hearts) I'd like to draw special attention to Kingdom Hearts which has anime inspired designs for its human characters but it draws deeply from the American Disney canon which would pose the question since its inspired by western culture does it qualify as a Western RPG as well? It's not as though a JRPG cannot be inspired by Western culture since the definition catches any RPG made in Japan but then we pose similar inquiries.
A few of the games on the list are considered JRPGs which I don't think many will have thought of as JRPGs unless brought up. Yakuza is a game heavily inspired by Japanese culture and is made in Japan but it's strange to think of it as an RPG at all. The games Yakuza is most similar to is GTA and other open world sandbox action/adventure games such as Sleeping Dogs and Just Cause not JRPGs such as Pokemon and Fire Emblem. So is Yakuza a JRPG? technically it is but the main genre would not be JRPG in the way that Mass Effect is technically a dating sim although you don't usually class it as such.
Another interesting entry is the Souls series and Dragon's Dogma both of which are RPGs made in Japan but are themed like generally western style RPGs similar to Baldur's Gate and The Elder Scrolls more than God Eater and Code Vein. It doesn't matter that much for them though because "souls-like" has seemingly become a genre in and of itself. That does beggar the question do all souls-like games count as JRPGs since according to Wikipedia they are inspired by a JRPG? Is Star Wars: Fallen Order a JRPG?? I'd say no because that just feels ridiculous but I think its more that inspired by JRPGs is mostly thought of as similar to early FF than similar to Yakuza.
A common thread here is tagging, a game can have any number of tags but you don't think of games as all of its constituent genres. When is a platformer not a platformer? When it's a Metroidvania or a collect-a-thon (think Banjo Kazooie) or an adventure game. The problem with genre is that its not often very useful at its broadest, Mario, Mark of the Ninja and Spelunky are all 2D platformers (which I'm defining as a 2D game with a jump button and platforms where jumping is necessary) but only Mario is thought of predominantly as a platformer, MotN is Stealth action game and Spelunky is a Roguelike. They're all undeniably platformers but they couldn't be more different and it isn't useful to think of the latter 2 as platformers. Genres also have confusing overlap and separations, what is a horror game? A simple way to think about it is a game that elicits horror, now what is the gameplay of a horror game like? Is it a visual novel (Higurashi)? A walking sim (Outlast), an FPS (Resident Evil)? Because any of these tags can describe a game's genre but as soon as its main objective is to elicit horror the main way people think of it is "horror game" regardless of mechanics. There's also games which are Horror secondary, Bioshock is usually thought of as an FPS with a horror tone but one tag describes gameplay the other describes emotions, when does one dominate the other? Its nebulous and I think that's a core problem with defining JRPGs. A lot of the games that qualify are not thought of as JRPGs they are thought of primarily as something else.
One more food for thought, RPGmaker is on the list, which might not even be considered a game, its a software to craft "RPG"s but that is not a game in the same way Unity and Flash are not games, they're tools. Are the games made using it considered JRPGs? The software has all the tools needed to make an RPG with turns, items, levelling and anything else you could think of to rip off early FF but you don't need to use any of them and you might just make a walking simulator (To the Moon) which is distinctly not an RPG. Okay now say you remove all combat, levelling and items from an early Final Fantasy (rendering it a walking simulator merged with a visual novel) is it still a JRPG? probably not, it'd no longer be an RPG, now add back in enough elements to make it an RPG, say you talk enemies into submission like in Fallout, wouldn't this make Ace Attorney a JRPG? A visual novel with "enemies to defeat", "inventory management", and "anime style characters". Most would still say no, Ace Attorney is generally considered a visual novel or a detective game but it mostly satisfies the requirements of a JRPG, granted, about as much as it counts as a romance game.
Here's the rub, JRPGs themselves at their inception are largely inspired by Western RPGs. Wizardry and Ultima are very direct influences on Dragon Quest, one of the prototypical JRPGs and anything closely inspired by it is considered a JRPG but who's to say a western game with cartoony graphics wasn't also inspired by Ultima rather than Dragon Quest? would it still be a JRPG? that's up for interpretation and guessing the developer intent. The problem with inspirations is it's somewhat of a tangled web and it's hard to say if something directly/solely inspired something else. An example would be the Suzanne Collins controversy when people noted Hunger Games bore a strikingly similar premise to Battle Royale both featuring a death game involving teens tasked to kill each other at the behest of a dystopian government. Collins claimed to have never heard of Battle Royale and instead gotten the idea from channel surfing between Survivor and news coverage of a war, despite the similarities I'm inclined to believe her without evidence to the contrary. The Running Man was a movie with a loose version of the premise from over a decade before Battle Royale was published and I wouldn't suggest Battle Royale is based on it but rather that a death game run by a dystopian government isn't that far fetched of an idea to independently come up with. Contrast to A Fistful of Dollars which is a very close retelling of Yojimbo which could not be refuted as a straight rip of the older film. Essentially, inspirations and intent is a tangled web and some games might get pulled into the JRPG genre despite not being directly influenced by a JRPG or being inspired by one.
Ultimately it comes back to perception, no one will argue Final Fantasy isn't a JRPG and no one will argue Call of Duty is a JRPG but where a definition needs to be careful is the grey area in between, I think most people would consider Genshin Impact a JRPG if you count games heavily inspired by JRPGs but not everyone agrees there. I don't personally consider Dust: An Elysian Tail a JRPG given it's predominately a Metroidvania (which falls under platformers usually) and neither Metroid nor Castlevania are considered RPGs, the art style is vaguely anime-lite but American cartoons can have a similar art style without being anime inspired but more than anything else because the game is lightly steeped in Korean culture, the game's cover has a Korean subtitle and a few references to Korean culture are mixed in such as Kimbap and the Halmeoni Pendant but I wouldn't fault someone who considers it a JRPG. And that's the takeaway, similar to questions like "What qualifies as anime?" or "What is a game?", I could try to define JRPG but where I draw the line in the sand you might disagree and where you draw the line I might disagree and neither of us are right or wrong unlike defining genres with stringent definitions like Roguelikes, Visual Novels or Souls-likes.