What does similarity mean?
Similarity means the quality of being alike in appearance, character, behavior, structure, or some other respect. It is commonly used when comparing two people, objects, situations, or ideas, and can refer to an obvious resemblance or to a precise correspondence measurable through particular features. The word is especially important in mathematics, where similar figures have matching angles and proportional dimensions even if they are different sizes, and in sciences such as biology, where genetic similarity indicates shared ancestry. In ordinary writing, “similarity” is a neutral and versatile term that can describe both broad likenesses and carefully defined correspondences. “Resemblance” is often used for visual or outward likeness, while “similitude” is more formal. Related words include “similar,” an adjective describing things that resemble one another, and “simile,” a literary comparison using “like” or “as.”
nounThe state or quality of being alike or similar in appearance, character, nature, or some other respect. It refers to a likeness or resemblance between two or more things.
- The quality of being alike or resembling something else.
- A likeness or correspondence between two or more people, objects, situations, or ideas.
"The similarity between the two paintings was immediately apparent."
"The study examined the similarity between human and animal communication."
"She noted a striking similarity between the two versions of the manuscript."
Used when referring to multiple examples or kinds of likeness, especially in formal or analytical contexts.
"The researchers compared the similarities and differences between the two species."
Similarity is one of mathematics’ simplest ideas and one of its most powerful: two figures can differ in size yet remain similar if their corresponding angles and proportions match.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does similarity come from?
Similarity comes through Middle English from Old French similitude, a borrowing of Latin similitudo, meaning “likeness” or “resemblance.” Latin similitudo was derived from similis, “like” or “similar,” with the suffix -tudo forming a noun of quality. The same Latin root appears in English words such as simile, similtude, and similar, while similtude also preserves the older English form of the Latin noun.
How similarity is actually used
Similarity is neutral and widely used in both formal and informal contexts. In scientific and mathematical contexts, it usually denotes a measurable correspondence in properties or structure; “resemblance” may suggest a more noticeable visual or qualitative likeness.
Easily confused with similarity
Similarity is the general quality of being alike, while a resemblance more often refers to a particular visual or outward likeness.
Similarity is the usual everyday term; similitude is more formal and can also mean a comparison or likeness expressed in a striking way.