Computer Science Glossary

The procedure a system uses to find patterns in training data.

Extra information written inside an opening tag, such as href or alt.

Proving that you are who you claim to be.

Carrying out a task with minimal human intervention.

Able to operate and make decisions without direct human control.

A separate copy of data kept so it can be restored if the original is lost.

The maximum amount of data a connection can carry per second.

A systematic error that pushes results consistently in one direction.

Systematic unfairness in results, usually caused by unrepresentative training data.

A single binary digit — either 0 or 1. The smallest unit of stored data.

The process of starting a computer and loading its operating system.

The slowest stage in a system, which limits the speed of everything else.

A test input at the edge of a valid range, where errors are most likely.

How a business is perceived by customers and the public.

The point at which total income equals total costs.

The amount of CPU time a process needs to complete.

A group of 8 bits; the standard unit for measuring file and memory size.

A customer adding items to an online basket but not completing the purchase.

A program that holds a conversation with a user in natural language.

Scrambled data after encryption.

One part of an SQL statement, such as WHERE or ORDER BY.

Grouping similar items together without predefined categories.

The unique number Unicode assigns to a particular character.

One attribute stored for every record in a table.

A note in the code, starting with #, ignored when the program runs.

Studying rival businesses to find gaps and opportunities.

Joining two strings end to end.

An expression evaluating to True or False that controls a branch or loop.

Saving one process's state and loading another's so the CPU can change tasks.

A visitor completing the desired action, such as making a purchase.

The process and cost of gaining a new customer.

Using digital tools to harass, threaten or humiliate a person.

A structured collection of data used to train or test a model.

A property and value pair inside a CSS rule, such as color: red.

Software that lets the OS communicate with a specific piece of hardware.

Promoting a product through online channels such as search, social media and email.

Taking only separate, fixed values with nothing in between.

The Document Object Model — the browser's live representation of the page that JavaScript can change.

An opening tag, its content and its closing tag taken together.

Scrambling data so only a key holder can read it.

AI designed so its decision-making can be understood by people.

A combination of values and operators that produces a result.

An input variable the model uses to make its prediction.

One item of data within a record — usually one column.

A file being stored in non-adjacent pieces across a disk.

A data set where one outcome is far more common than the other.

The position of an item in a list, counting from 0.

A loop whose condition never becomes False, so it never ends.

Another name for a NOT gate.

A numeric label uniquely identifying a device on a network.

Repeating a set of steps; a loop.

The known correct output attached to a training example.

A recorded history of events with timestamps.

A drawing showing gates and the connections between them.

Software written to damage a system or steal data.

A CSS rule that applies only when the screen meets a condition, such as a maximum width.

The result of training — what the system uses to make predictions.

A file of Python code that can be imported and reused.

Running several processes apparently at once by switching the CPU rapidly between them.

A computing structure loosely inspired by brain cells, arranged in connected layers.

Software whose source code is published and may be used and modified under its licence.

A value far outside the normal range, which may be an error or a genuine extreme.

When a model memorises its training data and performs poorly on new data.

What happens when a value is too large for the number of bits reserved for it.

To write new data on top of existing data, destroying the original permanently.

A small block of data sent across a network, carrying its own address information.

Moving fixed-size blocks of memory between RAM and disk.

Any information that can identify a living individual.

Presenting someone else's work or ideas as your own.

Readable data before encryption.

The output a model produces for an input it has not seen before.

A column whose value uniquely identifies each row.

The most likely explanation for a fault, formed before testing begins.

A request for specific data from a database.

The number of distinct digits a number system uses.

Data as originally collected, before any cleaning or processing.

One complete entry in a database table — usually one row.

A saved snapshot of system settings and files that can be returned to later.

Keeping existing customers buying over time.

How a business earns money from what it offers.

A device that forwards data between different networks.

One complete entry in a table.

The subset of a population actually surveyed or measured.

Measuring an analog signal at regular intervals to convert it to digital.

The ability to serve many more customers without a matching rise in costs.

Dividing customers into groups with shared characteristics.

Choosing between alternative paths based on a condition.

The part of a CSS rule that decides which elements the rule applies to.

A device that detects a physical property such as temperature or motion.

Determining whether a piece of text expresses a positive or negative opinion.

Steps carried out one after another in a fixed order.

A new business, usually built around an untested idea and aiming to grow quickly.

A single complete instruction in a program.

A smaller, self-contained part of a larger problem.

Systematic monitoring of people's behaviour or communications.

A device that forwards data only to the specific device it is addressed to.

The grammatical rules a programming language requires.

A structure of rows and columns holding related data in a database.

An HTML keyword in angle brackets that marks the start or end of an element.

The oval flowchart symbol marking the start or end of a process.

A state where the system spends more time paging than doing useful work.

A table recording how each variable changes as an algorithm runs.

The error report Python prints when a program fails, showing where and why.

A customer action that automatically causes a system to send a message.

A command that tells an SSD which blocks are no longer in use so it can manage them efficiently.

Total time from a process arriving to it finishing.

Converting a value from one data type to another.

A gate (NAND or NOR) from which every other logic gate can be built.

Memory such as RAM that loses its contents when power is removed.