diff --git a/ch11_blockchain.adoc b/ch11_blockchain.adoc
index 6b9e6938..621e6e28 100644
--- a/ch11_blockchain.adoc
+++ b/ch11_blockchain.adoc
@@ -591,7 +591,7 @@ other address prefixes or alterations.
 
 ===== Using testnet
 
-Bitcoin Core, like many other Bitcoin programs, has full support
+Bitcoin Core, like((("Bitcoin Core", "testnet"))) many other Bitcoin programs, has full support
 for operation on testnet as an alternative mainnet. All of Bitcoin Core's
 functions work on testnet, including the wallet, mining testnet coins,
 and syncing a full testnet node.