diff --git a/src/CLI2.cpp b/src/CLI2.cpp
index 4c5743865..e7f545636 100644
--- a/src/CLI2.cpp
+++ b/src/CLI2.cpp
@@ -1341,6 +1341,11 @@ void CLI2::desugarFilterAttributes ()
           op.attribute ("raw", ">");
           rhs.attribute ("raw", value);
         }
+        else if (mod == "by")
+        {
+          op.attribute ("raw", "<=");
+          rhs.attribute ("raw", value);
+        }
         else if (mod == "none")
         {
           op.attribute ("raw", "==");
diff --git a/src/Context.cpp b/src/Context.cpp
index d13b105ec..d6e58463e 100644
--- a/src/Context.cpp
+++ b/src/Context.cpp
@@ -397,6 +397,7 @@ static const char* modifierNames[] =
 {
   "before",     "under",    "below",
   "after",      "over",     "above",
+  "by",
   "none",
   "any",
   "is",         "equals",