fix English grammar
diff --git a/src/http/ngx_http_request.h b/src/http/ngx_http_request.h
index 0b269a8..9098a2a 100644
--- a/src/http/ngx_http_request.h
+++ b/src/http/ngx_http_request.h
@@ -449,7 +449,7 @@
     unsigned                          limit_zone_set:1;
 
 #if 0
-    unsigned                          cachable:1;
+    unsigned                          cacheable:1;
 #endif
 
     unsigned                          pipeline:1;