HAT 
History Aptitude Test. Oxford University admissions test for selection of candidates for all degree courses involving history. Taken in early November. See Admissions Testing Service. Tests for other subjects include:

Classics Admissions Test (CAT)
English Literature Admissions Tests (ELAT)
Geography Admissions Test (GAT)
National Admissions Test for Law (LNAT)
Mathematics Aptitude Test (MAT)
Modern Languages Admissions Test (MLAT)
Oriental Language Test (OLAT)
Physics Aptitude Test (PAT)
Sixth Term Examination Paper (STEP) taken in June
Thinking Skills (TSA)
Some of the above are exclusive to Oxford University, others are used by, inter alia, Cambridge University and are administered by a section of Cambridge Assessmant while LNAT is run by a consortium of universities and administered by Pearson

Head of Centre (HoC)
The Head of Centre is the most senior member of an education/ training organisation, usually the headteacher or principal of a school/college. The Head of Centre is responsible for ensuring the integrity of the administration and conduct of awarding organisation examinations, though in practice this responsibility is delegated to the Examination Officer.

Head of Department (HoD) or Head of Faculty or Head of Subject (HoS)
The usual point of contact between Examination Officers and a particular subject Department/Faculty. A member of that department/faculty may be in charge of a particular qualification type, such as GCE, GCSE. and vocational/technical qualifications. The precise title varies from school to school.

Head of Year (HoY)
Head of year (Pastoral Managers, Year Coordinator, Head of House) These managers (their title will vary from school to school depending on the way in which the school is structured) are responsible for the social welfare of the pupils within their year group or house. They will manage their team of form tutors who deal with pupil attendance and welfare.