The person responsible for running a particular department on a film or television production, e.g. the head of the camera department is generally the Director of Photography (DOP).
For the purposes of API funding, Heads of Department are as generally known in the industry and include Line Producer or Production Manager (where there is one only), DOP, 1st AD, Location Manager, Production Designer, Construction Head, Sound Recordist, Gaffer, Grip, Costumer Designer, Key Make-up Artist, Hair Supervisor, VFX Supervisor, Post Supervisor, Editor, Composer, Sound Designer, Production Accountant and, where the role is significant, Stunt, Safety, and SFX Co-ordinators/Supervisors.