Which word is used to describe something that is palace-like or magnificently enormous?

The term "palatial" is specifically used to describe something that is reminiscent of a palace, conveying an impression of grandeur or magnificence. This word encapsulates the idea of opulence and large scale, suggesting an architectural or aesthetic quality that is luxurious and impressive, similar to what one would expect from a grand palace.

In the context of the other options, while "colossal" implies something that is very large, it does not necessarily carry the connotation of elegance or luxury associated with palatial structures. Conversely, "tiny" and "modest" both denote smallness or simplicity, which are in direct contrast to the grandeur implied by palatial. Thus, "palatial" is the most fitting choice as it accurately embodies the characteristics of being magnificent and enormous in a way that suggests sophistication and splendor.