What is a tree dictionary in C.

Create your own dictionary with C ++

So, map and set were not known to me, but I took a quick look.

Maybe I'll dig a little to make it clear what exactly I'm trying to achieve:
I have the following goal:
I want to create a "help" for the smartphone app "4 Pictures 1 Word" (which is executed on the PC) as a simple console program.
For those who do not know the game: You get 4 pictures that represent a concept. Then you get 12 letters, of which you have to combine e.g. 5 to get the term you are looking for.
I have already created the code that will create all possible combinations of the given letters in the length I am looking for. Since this list naturally contains tons of words that do not exist, I wanted to filter them with a dictionary.

I would like to create this like this:
I feed several books (by Gutenberg) in .txt format into a console program. This formats the words (remove all capital letters, punctuation marks) and feeds them into a vector if they are not yet available.

I would like to sort this vector reasonably sensibly / create a tree or whatever and take over the whole structure in the other program.
As far as I have informed myself, that would be possible with a database, for example. But in my opinion that would be shot at with cannons and I don't want to get used to it if possible (I want to improve my C ++).

For this first type of dictionary it might still be possible to always read in a text file at the beginning of the program.
In a second step I would like to make the dictionary more efficient:
I want to create a tree where a node can have up to 26 children, one child for each letter of the alphabet.
So I could just follow a character path. If a character path is an existing word, a boolean variable in this node would be set to "true"; if the path does not exist, it is also not a valid word.
Exporting this structure as a text file and reading it in every time the user program is started seems a bit complicated to me.

That's why I'm looking for a way to export an entire data structure and use it in another program without going through the text file or a database ...

Edit: It's just about practicing a bit, of course you can argue about sense or nonsense here