Cambridge has its own names for things, which this page attempts to clarify. A much more extensive dictionary can be found here.

Term Explanation
CST Department of Computer Science and Technology
CL Computer Lab, the former name for the Department of Computer Science and Technology. Many (most?) people continue to refer to the Department as the Lab.
WGB The William Gates Building, where CST is located. This refers to Bill Gates’s father, William Gates, whose charitable donation contributed to the building.
Tripos A program of study. In medieval times, the final oral exam was conducted by an examiner sitting on a three-legged stool, hence the name.
UTO A ‘University Teaching Officer’, essentially someone who is employed by the university to teach.
Part 1A First year of the undergraduate program
Part 1B Second year of the undergraduate program
Part II Third (and final, for computer science students) year of the undergraduate program
Part III The one-year Master’s program
Overseer A UTO who looks over (but does not assess) Part II projects.
Tick A (typically short) programming project that is graded pass/fail for some UG courses
MPhil Also the one-year Master’s program, but for students who didn’t do a Cambridge UG degree
Viva Oral exam
Michaelmas The term that runs from early October to early December
Lent The term that runs from mid-January to mid-March
Easter The term that runs from mid-April to mid-June. Exams are held in Easter term.
UofA Unit of assessment
‘Wednesday’ The staff meeting held in the CST department every Wednesday
CDT A centre for doctoral training, typically a collaboration between multiple departments
Supervision Small-group instruction provided to undergraduates
B.A. Bachelor of Arts, the degree granted to most undergraduates, including those in computer Science
M.A Master of Arts, the degree granted to all B.A. holders automatically three years after graduation. Some university staff are also eligible for this degree after three years of full-time employment.
M. Phil Master of Philosophy. A degree awarded on completion of a one-year (actually, 9 month) program, for example, in computer science
M. Res Master of Research. A postgraduate degree granted in some programs, especially by Centres for Doctoral Training.
D. Sc Doctor of Science. A ‘higher doctorate’ that is granted to some people under some circumstances, as detailed in the link.