diff --git a/README.md b/README.md
index 42a57cd..419f84d 100644
--- a/README.md
+++ b/README.md
@@ -79,6 +79,7 @@ $ ./planck < bootstrap.fs example/fib.fs
 | \|   | or        | ( a b -- c )    | c = (a \| b)                 |
 | ^    | xor       | ( a b -- c )    | c = (a ^ b)                  |
 | <    | less      | ( a b -- c )    | c = (a < b)                  |
+| u    | uless     | ( a b -- c )    | c = (a unsigned< b)          |
 | =    | equal     | ( a b -- c )    | c = (a == b)                 |
 | v    | argv      | ( -- a-addr u ) | argv and argc                |
 | V    | impl      | ( -- c-addr )   | Implementation String        |