Identify the underlying concept of the following definition.
A metaphor is a figure of speech that compares two different things without using the words “like” or “as”.
The underlying concept of the definition is comparison or analogy.
Complete the following task based on the instruction and optional input provided.### Instruction:
Identify the underlying concept of the following definition.

### Input:
A metaphor is a figure of speech that compares two different things without using the words “like” or “as”.

### Output:
The underlying concept of the definition is comparison or analogy.