1.+Definition

** 1. a similarity between like features of two things, on which a comparison may be based **   2. similarity or comparability    3. Biology. an analogous relationship.    4. Linguistics.  a. the process by which words or phrases are created or re-formed according to existing patterns in the language, as when shoon was re-formed as shoes, when -ize is added to nouns like winter to form verbs, or when a child says footsfor feet. b. a form resulting from such a process.
 * a⋅nal⋅o⋅gy **

5. Logic. a form of reasoning in which one thing is inferred to be similar to another thing in a certain respect, on the basis of the known similarity between the things in other respects.

An analogy is a bit more complicated than a metaphor or a simile. At the most basic level, an analogy shows similarity between things that might seem different and it is much like an extended metaphor or simile. But analogy isn't just a form of speech. It can be a logical argument: if two things are alike in some ways, they are alike in some other ways as well. Analogy is often used to help provide insight by comparing an unknown subject to one that is more familiar. It can also show a relationship between pairs of things. This form of analogy is often used on standardized tests in the form "A is to B as C is to D."