diff --git a/Compiling-from-source.md b/Compiling-from-source.md
index bc0be69..325d0df 100644
--- a/Compiling-from-source.md
+++ b/Compiling-from-source.md
@@ -49,7 +49,7 @@ On ARM64:
 Other desired packages can also be installed at this time. Some useful ones not installed by default include
 git, openssh, wget, vim ...
 
-Open the apropriate MSys2 terminal for your architecture from the start menu. On X86_64 open MINGW64 to compile with GCC, on ARM64 open CLANGARM64 to compile with Clang.
+Open the apropriate MSys2 terminal for your architecture from the start menu. On x86_64 open MINGW64 to compile with GCC, on ARM64 open CLANGARM64 to compile with Clang.
 
 Ensure the correct one is used. GCC is recommended but is only avalable for x86_64 at this time. On ARM64 the only choice is Clang which has problems described in errata below.