Okay, I'll concede that one, my apologies. A tablebase is essentially a precomputed endgame solution for all positions with that many pieces. Likewise, it has an opening book, which is a database that contains moves for the first few turns of the game.
It's still a heuristic searcher when it's not using those though.
> If the engine is searching a position that is not in the tablebases (e.g. a position with 7 pieces)
and it speaks a lot about tablebases. What is it?