How do the words “like” and “as” signal a simile?

In the study of rhetoric, a simile is a figure of speech that functions as a trope—a device that creates a textural effect by comparing two ostensibly dissimilar phenomena.1

The words “like” and “as” serve as explicit markers that signal a simile by announcing the comparison to the reader or listener. By using these specific connectors, a speaker or writer creates a clear, direct analogy between two different things, highlighting a shared quality while maintaining the distinction between the two subjects.123

For example, stating “she is as fierce as a tiger” uses the word “as” to establish the comparison, whereas saying “I will sleep like a baby” uses “like” to draw a parallel between the speaker's state and that of an infant. This distinguishes the simile from a metaphor, which makes an implicit comparison by equating two things directly without using “like” or “as”.23