1. [adj]  (of persons) highest in rank or authority or office; "his arch rival"; "the boss man"; "the chief executive"; "head librarian"; "top administrators"
2. [adj]  most important element; "the chief aim of living"; "the main doors were of solid glass"; "the principal rivers of America"; "the principal example"; "policemen were primary targets"

CHIEF(A) is a 8 letter word that starts with C.