#1625509: describe behaviour of import lock
diff --git a/Doc/library/imp.rst b/Doc/library/imp.rst
index a0e5870..a40c5e5 100644
--- a/Doc/library/imp.rst
+++ b/Doc/library/imp.rst
@@ -114,10 +114,16 @@
.. function:: acquire_lock()
- Acquires the interpreter's import lock for the current thread. This lock should
+ Acquire the interpreter's import lock for the current thread. This lock should
be used by import hooks to ensure thread-safety when importing modules. On
platforms without threads, this function does nothing.
+ Once a thread has acquired the import lock, the same thread may acquire it
+ again without blocking; the thread must release it once for each time it has
+ acquired it.
+
+ On platforms without threads, this function does nothing.
+
.. versionadded:: 2.3