Need help with description

I am developing a game. The units in it can attack one tile straight in any direction, but not diagonally. The unit is U, and it can attack the tiles marked “x”.

0 x 0
x U x
0 x 0
Lets say it attacks the tile to the right:

0 0 0
0 U x
0 0 0
Now, some units also affects other tiles, marked “?” Such as:

0 0 ?
0 U x
0 0 ?

or

0 ? ?
0 U x
0 ? ?
How can I describe which tiles are affected (The ones marked with “?”), using English instead of diagrams? I am stumped.

I don’t understand the use of the ? marks in the OP. In the third diagram, are the ? cells affected by the U or by the x? Same question for the fourth diagram (it is hard to tell which piece is affecting which cells).

If everything happens on the horizontally or vertically adjacent cells (and never on the diagonal), then early in the documentation you could define the term “adjacent” to mean “horizontally or vertically adjacent”.

The U is attacking the “x” as well as affecting the “?”.

Yes, I have done exactly that, and used adjecant to mean horizontally and vertically.

Any tiles that are adjacent to both the attacker (U) and the defender (x). Assuming adjacent is defined as any of the 8 tiles surrounding the subject tile.

Maybe use compass points. Say that a piece can attack north, south, east, and west or north, northeast, east, southeast, and south.

“Touching both U and X”.