A lot vs. Alot: 9 Grammatical Pitfalls
late 14c., from Latin simile "a like thing; a comparison, likeness, parallel," neuter of similis "like" (see similar). Both things must be mentioned and the comparison directly stated. To Johnson, "A simile, to be perfect, must both illustrate and ennoble the subject."
A common figure of speech that explicitly compares two things usually considered different. Most similes are introduced by like or as: “The realization hit me like a bucket of cold water.” (Compare metaphor.)
Note: Some similes, such as “sleeping like a log,” have become clichés.