As all terms, this is subject to opinion and context. In the word meaning, it means blood. But also dirt and mud. And if you gore something (as a verb), it is similar to stabbing.
A context synonym would be splatter.
In content media, such as games and movies, gore means lots of blood and often enough the surroundings that lead to that blood being there. Such media usually has an age rating of 18+ or is at least intended for not only a mature audience, but also fans of the horror/splatter/gore genre. Think Zombie Movies that are not comedies.
If they specifically except gore and not "violence" or "blood" or "mature topics and graphcis" you should be quite safe with any content. If not, you should question the non adult setting of your game.