Synonyms: likeness, similarity, similitude, resemblance, analogy, affinity
These nouns denote agreement or conformity. Likeness implies close agreement: It was your uncanny likeness to my brother that made me stare at you.
Similarity and similitude suggest agreement only in some respects or to some degree: They were drawn to each other by similarity of interests. A striking similitude between the brother and sister now first arrested my attention (Edgar Allan Poe).
Resemblance refers to similarity in external or superficial details: The child . . . bore a remarkable resemblance to her grandfather (Lytton Strachey).
Analogy is similarity, as of properties or functions, between things that are otherwise not comparable: The operation of a computer presents an interesting analogy to the working of the human brain.
Affinity is likeness deriving from kinship or from the possession of shared properties or sympathies: Being an orphan, she felt an affinity with other parentless children.