What is the term for the state of being similar or a feature that makes two things alike?

The term that best captures the state of being similar or a feature that makes two things alike is "likeness." This word encompasses not just the concept of similarity but also implies a visual or perceptual resemblance between two items. "Likeness" conveys the idea of shared characteristics or features that create a sense of similarity, making it the most appropriate choice for this definition.

In contrast, "imitation" refers more specifically to the act of copying something rather than simply sharing characteristics. "Similarity" also describes the concept of being similar but is often used in a more abstract sense. "Correspondence" usually implies a relationship or connection rather than simply being alike, focusing more on how two things relate to each other rather than their resemblance. Thus, "likeness" stands out as the term that best embodies the notion of a feature that makes two things alike.