The phrase Black Lives Matter (BLM), from the movement originating in 2013, shifts between a critique of Black lives taken as matter (understood as inhuman or subhuman) and the sense that Black lives, with queer and trans lives at their center, have consequence. These statements suggest two of the definitions used for materiality itself—one, a Marxist analysis pointing to the potency of a proletariat class under racial capitalism, for instance, and two, the racialization of a seemingly ordinary relationship between life and its material constituents. I am writing in June 2020 as the movement has invigorated multiple forms of reckoning around anti-Blackness and police violence and given force to prison abolition, economic and environmental justice, racial and health justice, and other linked movements. The BLM phrase would seem to borrow without interference on the immutable structure of a word like matter and its fixed senses. However, the ongoing use of language always informs the meaning a word eventually acquires, a point made in discussions of performativity (Austin 1975). Use can also become critique, as with queer; words matter and also perform mattering (J. Butler 1996). The racist description of nonwhite human lives regularly participates in the rendering of (and correlates...