diff --git a/include/mbedtls/aes.h b/include/mbedtls/aes.h
index 27be761..22eb116 100644
--- a/include/mbedtls/aes.h
+++ b/include/mbedtls/aes.h
@@ -314,7 +314,7 @@
  *             2. Use a randomly-generated \p nonce_counter for each call.
  *             With this strategy, you need to ensure the nonce is generated
  *             in an unbiased way and you must not encrypt more than 2**64
- *             block of data.
+ *             blocks of data.
  *
  *             Note that for both stategies, the limit is in number of blocks
  *             and that an AES block is 16 bytes.