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AQA A LEVEL COMPUTER SCIENCE KEY TERMS STUDY GUIDE
LATEST UPDATE -2026- 100+ QUESTIONS AND VERIFIED
ANSWERS ALL THE BEST
Application programming interface (API)
A layer of software that allows application programs to call on the services of the
operating system.
Association
If the relationship is not inheritance and it is not aggregation then it is an
association.
Broadband
A multiple data channel system in which the bandwidth of the transmission
medium carries several data streams at the same time.
Bubble sort
A sorting algorithm where during a pass, neighbouring values are compared and
swapped. Passes are made until no further swaps are needed.
Absolute Error
The difference between the actual number and the nearest representable value.
Abstract data type (ADT)
A data type whose properties are specified independently of any particular
programming language.
Asymptotic behaviour of f
It is the behaviour of the function f(n) for very large values of n.
, 2
Asynchronous serial data transmission
Transmission system in which the sender and receiver have separate clocks which
are not kept synchronised. Instead, the clocks are synchronised temporarily at the
start of a transmission. The arrival of data cannot be predicted by the receiver; s a
start bit is used to signal the arrival of data and to synchronise the transmitter and
receiver temporarily.
Attribute
A property or characteristic of an entity (databases) or an object (OOP).
Automation
Turning an abstraction into a form that can be processed by a computer.
Backus-Naur Form, (BNF)
Backus-Naur Form, (BNF)
Bandwidth
For a transmission medium, the range of signal frequencies it may transmit.
Base case
A value that has a solution which does not involve any reference to the general
case solution.
Baseband system
A system that uses a single data channel system in which the whole bandwidth of
the transmission medium is dedicated to one data channel at a time.
Basic operation
The operation which contributes most to the total running time.
Baud rate
The rate at which signals on a wire may change.
Behaviours
, 3
The functions of the object or what the object does.
Bit rate
The number of bits transmitted per second
Abstraction
Representation that is arrived at by removing unnecessary details.
Aggregation
Relationship between two object types in which one object type has a component
which is of the other type.
Ajax
Web technology that allows only the part of a web page that needs updating to be
fetched from the web server.
Algorithm
A sequence of unambiguous instructions for solving a problem. It can be
represented as a Turing machine program.
Cipher text
Message data after it has been encrypted.
Circular queue
When the array element with the largest possible index has been used, the next
element to join the queue reuses the vacated location at the beginning of the
array.
Class definition
A template that can be used to create objects of that class.
Client
A computer that uses the services provided by a server.
Client-server system
AQA A LEVEL COMPUTER SCIENCE KEY TERMS STUDY GUIDE
LATEST UPDATE -2026- 100+ QUESTIONS AND VERIFIED
ANSWERS ALL THE BEST
Application programming interface (API)
A layer of software that allows application programs to call on the services of the
operating system.
Association
If the relationship is not inheritance and it is not aggregation then it is an
association.
Broadband
A multiple data channel system in which the bandwidth of the transmission
medium carries several data streams at the same time.
Bubble sort
A sorting algorithm where during a pass, neighbouring values are compared and
swapped. Passes are made until no further swaps are needed.
Absolute Error
The difference between the actual number and the nearest representable value.
Abstract data type (ADT)
A data type whose properties are specified independently of any particular
programming language.
Asymptotic behaviour of f
It is the behaviour of the function f(n) for very large values of n.
, 2
Asynchronous serial data transmission
Transmission system in which the sender and receiver have separate clocks which
are not kept synchronised. Instead, the clocks are synchronised temporarily at the
start of a transmission. The arrival of data cannot be predicted by the receiver; s a
start bit is used to signal the arrival of data and to synchronise the transmitter and
receiver temporarily.
Attribute
A property or characteristic of an entity (databases) or an object (OOP).
Automation
Turning an abstraction into a form that can be processed by a computer.
Backus-Naur Form, (BNF)
Backus-Naur Form, (BNF)
Bandwidth
For a transmission medium, the range of signal frequencies it may transmit.
Base case
A value that has a solution which does not involve any reference to the general
case solution.
Baseband system
A system that uses a single data channel system in which the whole bandwidth of
the transmission medium is dedicated to one data channel at a time.
Basic operation
The operation which contributes most to the total running time.
Baud rate
The rate at which signals on a wire may change.
Behaviours
, 3
The functions of the object or what the object does.
Bit rate
The number of bits transmitted per second
Abstraction
Representation that is arrived at by removing unnecessary details.
Aggregation
Relationship between two object types in which one object type has a component
which is of the other type.
Ajax
Web technology that allows only the part of a web page that needs updating to be
fetched from the web server.
Algorithm
A sequence of unambiguous instructions for solving a problem. It can be
represented as a Turing machine program.
Cipher text
Message data after it has been encrypted.
Circular queue
When the array element with the largest possible index has been used, the next
element to join the queue reuses the vacated location at the beginning of the
array.
Class definition
A template that can be used to create objects of that class.
Client
A computer that uses the services provided by a server.
Client-server system
