Spinoza’s definition of ‘attribute’ has been described as ‘one of the most puzzling passages in the Ethics’ and ‘a longstanding worry’ for Spinoza interpreters. Its puzzling status stems from its apparent ‘subjectivist’ character and the dominant understanding of Spinoza’s notion of attribute as an ‘objectivist’ notion. The paper aspires to remove this puzzlement by proposing and defending a reading of E1d4 in which it is understood to have two senses. First, I defend the objectivist character of Spinoza’s notion of attribute, (...) and explain why E1d4 is problematic within the framework of an objectivist interpretation of the Spinozistic attribute. Second, I propose a reading of E1d4 as having two senses and explain the cause of an apparent contradiction in E1d4. Finally, I devote the largest part of the paper to a defence of the Two-Sense Reading of E1d4. More specifically, I draw on four sources for this defence: the structure of E1d1 and E1d3, the content and form of E1p4 and its demonstration, Spinoza’s doctrine of parallelism and Descartes’ treatment of attribute and its influence on Spinoza. (shrink)