IB · Diploma Programme · IBDP CS (SL/HL)
Computer Science — Keywords & Key Terms — Definitions Glossary (2026)
International Baccalaureate Diploma Programme Computer Science (SL/HL)
Topic-by-topic keywords, key terms and definitions for precise exam language—separate from our revision checklists (topic coverage) and formula sheets (equations).
Keywords & Key Terms — definitions
Examiner-style keywords and definitions organised by syllabus topic. Terms are tagged Essential (start here), Core (typical exam standard), and Advanced for harder distinctions — tick each row when you can recall it. Your progress is saved in this browser for this list.
IB Diploma Programme Computer Science (IBDP CS (SL/HL))
IB Diploma Programme Computer Science (IBDP CS (SL/HL))
International Baccalaureate Diploma Programme Computer Science (SL/HL)
Topics map to the IB DP Computer Science syllabus: System fundamentals, Computational thinking, Software engineering, Networks and databases, plus an HL Option (e.g. Modelling and simulation, Web science, or Computational thinking).
Mark schemes: IB CS mark schemes reward precise terminology and command-term-driven responses (define, outline, explain, analyse, evaluate). Pseudocode must follow the IB approved notation; algorithm efficiency answers must reference Big-O.
Active recall: 0 / 42 terms ticked
| Recalled | Topic | Level | Keyword | Definition |
|---|---|---|---|---|
| System Fundamentals | Essential | Bit | Smallest unit of digital data; represents either 0 or 1. | |
| System Fundamentals | Essential | Byte | Group of 8 bits; standard unit for representing a single character. | |
| System Fundamentals | Core | Binary | Base-2 number system using only 0 and 1; the native representation in digital systems. | |
| System Fundamentals | Core | Hexadecimal | Base-16 number system (0–9, A–F); compact representation of binary. | |
| System Fundamentals | Core | ASCII / Unicode | Character encoding standards mapping integers to characters; Unicode supports international scripts. | |
| System Fundamentals | Core | CPU (Central Processing Unit) | Hardware component that executes instructions via fetch–decode–execute cycle. | |
| System Fundamentals | Core | RAM (Random Access Memory) | Volatile primary memory used to hold currently running programs and data. | |
| System Fundamentals | Advanced | Cache memory | Small high-speed memory storing frequently accessed data to reduce CPU wait time. | |
| System Fundamentals | Advanced | Virtual memory | Technique using secondary storage to extend apparent RAM capacity via paging. | |
| Computational Thinking and Problem Solving | Essential | Algorithm | Finite, ordered sequence of unambiguous steps that solves a problem. | |
| Computational Thinking and Problem Solving | Essential | Pseudocode | Structured English-like notation for expressing algorithms independently of any language. | |
| Computational Thinking and Problem Solving | Core | Abstraction | Process of removing unnecessary detail to focus on the essential features of a problem. | |
| Computational Thinking and Problem Solving | Core | Decomposition | Breaking a problem into smaller, more manageable sub-problems. | |
| Computational Thinking and Problem Solving | Core | Linear search | Search algorithm checking each element in turn; worst-case complexity O(n). | |
| Computational Thinking and Problem Solving | Core | Binary search | Search algorithm on sorted data that halves the search space each step; complexity O(log n). | |
| Computational Thinking and Problem Solving | Core | Bubble sort | Simple sorting algorithm with worst-case complexity O(n²). | |
| Computational Thinking and Problem Solving | Advanced | Big-O notation | Asymptotic notation describing algorithm efficiency: O(1), O(log n), O(n), O(n log n), O(n²). | |
| Computational Thinking and Problem Solving | Advanced | Recursion | Algorithm that calls itself with a reduced input until a base case is reached. | |
| Software Engineering and Programming Paradigms | Essential | Variable | Named storage location holding a value that may change during execution. | |
| Software Engineering and Programming Paradigms | Essential | Function / method | Reusable named block of code that performs a specific task; may return a value. | |
| Software Engineering and Programming Paradigms | Core | Procedural programming | Paradigm structuring code as procedures (functions) operating on data. | |
| Software Engineering and Programming Paradigms | Core | Object-oriented programming (OOP) | Paradigm modelling code as interacting objects with state and behaviour. | |
| Software Engineering and Programming Paradigms | Core | Encapsulation | Bundling data and methods within a class and restricting direct access to internal state. | |
| Software Engineering and Programming Paradigms | Core | Inheritance | Mechanism by which a subclass acquires attributes and methods from a parent class. | |
| Software Engineering and Programming Paradigms | Core | Polymorphism | Ability of objects of different classes to respond to the same method call in their own way. | |
| Software Engineering and Programming Paradigms | Advanced | Abstract class | Class that cannot be instantiated; defines a contract for subclasses to implement. | |
| Software Engineering and Programming Paradigms | Advanced | Design pattern | Reusable solution to a common software design problem (e.g. Singleton, Observer). | |
| Networks and Databases | Essential | Network | Two or more computers connected to share data and resources. | |
| Networks and Databases | Essential | Protocol | Set of rules governing data communication between devices. | |
| Networks and Databases | Core | TCP/IP | Layered protocol suite that underpins the internet; provides reliable end-to-end transmission and routing. | |
| Networks and Databases | Core | HTTP / HTTPS | Application-layer protocols for transferring web resources; HTTPS adds TLS encryption. | |
| Networks and Databases | Core | SQL SELECT statement | Query retrieving rows from one or more tables: SELECT cols FROM table WHERE condition. | |
| Networks and Databases | Core | Primary key | Field uniquely identifying each record in a relational database table. | |
| Networks and Databases | Core | Normalisation | Process of organising tables to reduce redundancy and dependency (1NF, 2NF, 3NF). | |
| Networks and Databases | Advanced | Symmetric encryption | Encryption using the same key for both encryption and decryption (e.g. AES). | |
| Networks and Databases | Advanced | Asymmetric encryption | Public-key cryptography using a public/private key pair (e.g. RSA). | |
| HL Option — Modelling, Web Science, Computational Thinking | Core | Simulation | Computer model imitating the operation of a real-world system over time. | |
| HL Option — Modelling, Web Science, Computational Thinking | Core | Search engine indexing | Process of crawling and storing web pages so they can be retrieved by query. | |
| HL Option — Modelling, Web Science, Computational Thinking | Core | PageRank | Algorithm ranking web pages by the number and quality of incoming links. | |
| HL Option — Modelling, Web Science, Computational Thinking | Core | Machine learning | Algorithms that improve performance on a task as they are exposed to more data. | |
| HL Option — Modelling, Web Science, Computational Thinking | Advanced | Stochastic model | Model incorporating random variables to represent uncertainty in inputs. | |
| HL Option — Modelling, Web Science, Computational Thinking | Advanced | Web 3.0 / semantic web | Web technologies enabling machine-readable, linked, semantically meaningful content. |
Pair this with our revision checklists, formula sheets hub and past paper finder.
Computer Science (IBDP CS (SL/HL)) — Keywords & Key Terms FAQ
- What is on this IB Diploma Programme Computer Science keywords and key terms list?
- It is a topic-organised glossary of important computer science terms with short, exam-style definitions aligned to International Baccalaureate Diploma Programme Computer Science (SL/HL) (IBDP CS (SL/HL)). It is designed for “define”, “state”, “outline” and “explain” questions where precise vocabulary earns marks.
- How should I use this Computer Science glossary alongside past papers?
- Tick terms when you can recall them without reading the answer, then check your wording against mark schemes. Pair vocabulary practice with past papers for Diploma Programme Computer Science (IBDP CS (SL/HL)) so you apply terms in context.
- Is this the same as a revision checklist or a formula sheet?
- No. Revision checklists help you track which syllabus topics you have covered and your confidence—separate pages on Tutopiya. Formula sheets summarise equations and quantitative relationships. This page is only a definitions and key-terms glossary for Computer Science.
- Can I download this Computer Science keywords and key terms list for free?
- Yes. After a quick free sign-up you can download a UTF-8 CSV (opens in Excel or Google Sheets) or open a print-friendly page and save as PDF. Browsing the list on the page is free.
- Is this Computer Science list aligned to the IBDP CS (SL/HL) specification?
- Topic groupings and wording follow International Baccalaureate Diploma Programme Computer Science (SL/HL) for IB Diploma Programme. Always confirm final learning objectives and any regional options in your official specification and recent examiner reports for your exam session.
- Why focus on definitions instead of full notes?
- Mark schemes reward correct technical terms and clear links between ideas. A compact glossary lets you drill the exact language examiners expect for Computer Science at Diploma Programme, separate from longer notes or topic trackers.