diff --git a/pyproject.toml b/pyproject.toml
index 19a6094..fd3dd24 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -57,7 +57,7 @@ jcs = "*"
 bitarray = "*"
 
 [tool.poetry.extras]
-turbo = ["cython"]
+cython = ["cython"]
 
 [tool.poetry.group.test.dependencies]
 pytest = "*"