in chief

• IPA^(key): /ɪn t͡ʃiːf/
• Rhymes: -iːf

in chief

1. (after a noun) Executive, the highest in command.
2. (heraldry) Used other than figuratively or idiomatically: see in,‎ chief. In the chief of the escutcheon.
   • 1844, John Burke, Bernard Burke, Encyclopædia of Heraldry, Or General Armory of England, Scotland and Ireland, page 375:

     Erm. a fesse betw. two demi lions in chief and three mascles in base gu.

   • 1874, John Woody Papworth, An Alphabetical Dictionary of Coats of Arms Belonging to Families in Great Britain and Ireland: Forming an Extensive Ordinary of British Armorials : Upon an Entirely New Plan ..., page 1070:

     Arg. a saltire betw. a cross-gate in chief and in base and a crescent in each flank gu. / HEGENS, Scotland. Arg. a saltire engr. betw. a mullet in chief two crescents in flanks and a cross crosslet fitchy in base gu.

• In the sense "executive", usually used after nouns denoting an occupation.