Same-Except is a fundamental domain-general cognitive relation in which entities in proximity to one another are judged to be the Same, Except for some part or property where they differ. This relation can be attested in non-linguistic modalities such as vision, audition, and taste, and it plays an important role in non-linguistic categorization. The chapter shows that this relation is expressed linguistically by means of a wide range of devices, including (a) lexical expressions such as same and except, (b) contrastive stress, (c) anaphora (e.g. definite and indefinite NP anaphora and VP anaphora), (d) ellipsis (e.g. bare argument ellipsis, sluicing, gapping, and VP-ellipsis), and (e) fixed expressions such as vice versa. This approach thereby unifies the semantics of all these phenomena under a common account that is based on a domain-general cognitive principle. The approach is compared with accounts of ellipsis based on syntactic copying or deletion, showing that both approaches have their difficulties.