Definitions may be fixed (using the f. adverb) to replace all component verbs by their definitions. This allows a verb which has been build of many component verbs to be made independent of changes made to these component verbs. For example:

   mean =. sum % count
     count=. #
     sum =. +/
   MEAN=. mean f.

   a=. 2 3 5 7 11
   mean a
5.6
   MEAN a
5.6

   mean
┌───┬─┬─────┐
│sum│%│count│
└───┴─┴─────┘
   MEAN
┌─────┬─┬─┐
│┌─┬─┐│%│#│
││+│/││ │ │
│└─┴─┘│ │ │
└─────┴─┴─┘

   sum=. */
   mean a
462
   MEAN a
5.6