diff --git a/Scala-modularization-and-classpaths.md b/Scala-modularization-and-classpaths.md
index 1dff140..2375074 100644
--- a/Scala-modularization-and-classpaths.md
+++ b/Scala-modularization-and-classpaths.md
@@ -2,7 +2,9 @@
 
 Scala modularization makes it necessary to deal with some existing issues that mainly relate to the (Java) boot classpath and to using Scala jars from a `lib/`.
 
-## Java boot classpath
+## Java boot classpath (bootstrap classpath)
+
+The term "boot classpath" comes from Java's Bootstrap Classes, which are the classes that implement the Java Platform. By default, bootstrap classes are in the `rt.jar` and several other jar files in the `jre/lib` directory according to [How Classes are Found](https://docs.oracle.com/javase/8/docs/technotes/tools/findingclasses.html).
 
 For the Java boot classpath, the `scala` launcher justs puts everything in `lib/` on it.
 This is not the right thing to do because it makes available classes not on the user's classpath.