diff --git a/lib/resolv.rb b/lib/resolv.rb
index d8ee487cfc..6d34a67e09 100644
--- a/lib/resolv.rb
+++ b/lib/resolv.rb
@@ -908,7 +908,7 @@ class Resolv
           values = Array(values)
           values.each do |t|
             Numeric === t or raise ArgumentError, "#{t.inspect} is not numeric"
-            t > 0.0 or raise ArgumentError, "timeout=#{t} must be postive"
+            t > 0.0 or raise ArgumentError, "timeout=#{t} must be positive"
           end
           @timeouts = values
         else