Proper use of the word "tableau"

Here's the dictionary definition:

1. a picture, as of a scene.

2. a picturesque grouping of persons or objects; a striking scene.

3. a representation of a picture, statue, scene, etc., by one or more persons suitably costumed and posed.

4. Solitaire. the portion of a layout to which one may add cards according to suit or denomination.

Usually, I've gotten the impression that this refers to board games that use cards or tiles that are arranged to create a board, like Forbidden Island/Desert or Carcassonne (maybe? Edit: no, that's just tile laying), and even an ordered layout like playing Solitaire. But I've also seen the term used to reference games like yours, with individual player boards that are separate from a main board. Seems like the "board game" definition of Tableau is still kind of vague, and can be used more "loosely".

7 wonders uses player boards that have a scene that represents a civilization and its particular Wonder. That fits the dictionary definition #1 above, and kind of relates to #2 & #3.

Starting with the BGG definition;
"In Tableau Building games, each player has a visible personal array or tableau of components (cards, tiles, player boards, etc.) which they purposefully build or manipulate throughout the game by spending actions and/or resources (including opportunity costs) and which determines the quality, quantity, and/or variety of actions to which they have access throughout the game.
The array is not merely a place to store resources, to plan out actions, to store a puzzle which must be manipulated, or something that impacts VP's. It impacts the quality, quantity, and/or variety of actions which are accessible to a player. This means that some games may include an array or a tableau but not really be a tableau building game."

I would say, as mentioned above, Tableau in the context of board games has a very loose or fluid definition but it does seem to refer to a variety of objects that are used to construct what is, essentially, your personal play area/player board/engine.

You have a single player board however, so I would not necessarily call it a tableau (it's certainly not an array of components, outside of constructing your army on top of it).

Perhaps stick with Player Board as I feel that's going to cause the least confusion.

Alternately you could come up with a thematic name, so long as it's referenced at the start of the rules so there is no confusion as to what players are looking at.