diff --git a/docs/api_reference/src/quantities.tex b/docs/api_reference/src/quantities.tex
index 0f171d13d..e317d2df6 100644
--- a/docs/api_reference/src/quantities.tex
+++ b/docs/api_reference/src/quantities.tex
@@ -2052,7 +2052,7 @@
 \pnum
 \begin{example}
 \begin{codeblock}
-// The first signature defines a base unit.
+// The first signature defines a base unit restricted to a kind of quantity.
 inline constexpr struct second final : named_unit<"s", kind_of<time>> {
 } second;