As nouns the difference between drills and trills
is that drills is plural of lang=en while trills is plural of lang=en.
As verbs the difference between drills and trills
is that drills is third-person singular of drill while trills is third-person singular of trill.
drills
English
Noun
(head)
Verb
(head)
(drill)
----
trills
English
Noun
(head)
Verb
(head)
(trill)