“instructors” is a form of
instructor
/ɪnˈstɹʌktɚ/ noun
Forms instructors instructour
Synonyms
Etymology
From Latin instructor, equivalent to instruct + -or.
Webster’s 1913
Etymology [L., a preparer: cf. F. instructeur.]
Sources: Wiktionary · WordNet 3.0 · Webster’s 1913 — from the Wiktionary entry “instructor”, CC BY-SA 4.0. Details