What is a comparison based on similarity between things that are otherwise dissimilar

Answer: Analogy.

Explanation:

An analogy is a comparison made between ideas/things that are often quite different. Analogy is more elaborate and detailed than a metaphor or a simile.

An example of an analogy is found in Shakespeare's Romeo and Juliet, Act II, Scene II. Juliet explains that her love for Romeo will remain the same, even if he changes his name. Similarly, a rose will always smell sweet, regardless of the name by which it is called:

"What's in a name? That which we call a rose

By any other word would smell as sweet.

So Romeo would, were he not Romeo called"