Decoding the International Baccalaureate (IB) Terminology: A Comprehensive Glossary

This glossary provides an overview of key terms and concepts used within the International Baccalaureate Diploma Programme (IBDP) and International Baccalaureate Career-related Programme (IBCP). Familiarising yourself with these terms will help you navigate and better understand these programs and their associated terminology.

The IBDP and the IBCP have their own terminology and abbreviations so here are some terms you may encounter when interacting with them. This glossary provides explanations for general IB terms:

IB Learner Profile

A set of ideals that inspire, motivate, and guide the work of schools and teachers within the International Baccalaureate programs. It unifies them under a common purpose and outlines the desired learning outcomes for each student.

Candidate Number

An identification number assigned to every IB candidate. The number changes between a student’s junior and senior year. The first four digits represent The Montessori School code, followed by a two-digit alphanumeric number.

Creativity – Activity – Service

Creativity – Activity – Service (CAS) is a significant requirement for IB students outside the classroom. Students in Year 11 and Year 12 must complete a senior long-term project involving at least 150 hours of documented activities in the areas of creativity, action, and service. They must also meet eight specific learning outcomes. An oral presentation in March serves as the culmination of their CAS requirements.


The title given to the person responsible for overseeing the day-to-day operations of the IB program. The Coordinator arranges schedules and examinations, advises students, and communicates the IB philosophy to students, faculty, and parents.


Descriptors are course-specific expectations or criteria used by teachers to evaluate and grade internal assessment assignments in all subjects. These descriptors provide clear guidelines and benchmarks for assessing student performance in relation to the specific requirements of each subject. They help ensure consistent and fair evaluation of student work across different classrooms and teachers within the IB program. By using descriptors, teachers can effectively assess and provide feedback to students based on each subject’s established standards and learning outcomes.

Extended Essay

During the IB Program’s two years, students write an original essay of up to 4000 words on a topic of their choice. They receive supervision from an IB teacher who mentors them throughout the research process for the essay.

Groups (1-6)

IB refers to subjects as groups. Here is the breakdown:

  • Group 1: Language and Literature.
  • Group 2: Second Language (e.g., French, Latin, Spanish).
  • Group 3: Individuals and Societies (social studies).
  • Group 4: Experimental Sciences.
  • Group 5: Mathematics.
  • Group 6: Arts and Electives

Group 4 Project

An interdisciplinary science and computer project that students design and present with the guidance of their science teacher.

HL/SL (Higher Level/Standard Level)

Diploma students take a combination of six IB courses: three Higher Level (HL) courses and three Standard Level (SL) courses. Higher Level courses are two-year courses culminating in May of the senior year, involving at least 270 hours of instructional time.

Internal Assessment

Internal Assessment (IA) refers to various assignments within each subject conducted throughout the course. These assignments are assigned and evaluated by the teacher, and a sample set is sent to a moderator for validation or adjustment of the marks assigned by the classroom teachers. For example, in History, the IA is a research project on a topic chosen by the student, while in Science, the IA consists of the documented record of the student’s lab work.

Language A1

Language A1 refers to an individual’s first language. At our school, the Language A1 course is taught in English. The syllabus focuses on literature and encompasses works from various authors around the world. Students engage with literary texts, analyse their themes, techniques, and cultural contexts, and develop critical thinking and writing skills within the framework of their first language.

Language B

Language B refers to a language that students learn as a second language. The aim of this course is to develop proficiency in listening, speaking, reading, and writing skills in the chosen language. At our school, students learn German. The course emphasises practical language usage, cultural understanding, and effective communication in real-life situations.


The process by which IB validates or adjusts the marks on internal assessments graded by classroom teachers. Samples of graded work for each IA are sent to moderators, who moderate the marks up or down to determine final marks/grades for that component.

Oral Commentary

In English and second language courses, each student delivers an oral presentation that is recorded for internal assessment. Samples of these recordings are sent by the teacher for moderation of all scores. This assessment allows students to demonstrate their oral communication skills and their ability to analyse and discuss literary or linguistic elements within the designated language.

Papers (1, 2, 3)

This term refers to examination papers in the IB context. Each subject requires at least two and sometimes three papers as part of the IB exam for that subject.


Learn more about the International Baccalaureate.

Find out more about the International Baccalaureate Diploma Programme and the International Baccalaureate Career-related Programme.