Computer Science
Essentials PLTW Terms
2026 | Key Terms, Study
Guide, Practice Questions,
Answers & Exam Review |
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,abstraction A technique or process that manages complexity in a program or computer system.
Abstraction "hides" details or removes duplication, allowing the programmer to
focus on high-level considerations and functions rather than the rules of a
programming language.
accumulator A role that a variable may take on in which it keeps a running or cumulative total or
value. Commonly an accumulator is initialized outside of a loop, assigned new
values within the loop, and then its result is used outside of the loop.
aggregator A variable that adds together all the values or data at a specific moment.
algorithm A set of steps to accomplish a task. An algorithm can be expressed in many kinds of
notation, such as natural language, pseudocode, and flowcharts. Algorithms are
essential to the way computers process data, because they contain the specific
instructions for what a computer or program does.
API An application programming interface is a set of program routines, protocols, and
tools that facilitates communication with a client app that is designed specifically for
the server. A client computer program can send instructions to the server and get
data from the server through the API.
app A software application, especially one that a user downloads to a mobile device.
argument The values that a program provides to a function or subroutine. Sometimes coding
professionals use the terms "argument" and "parameter" interchangeably. In this
course, argument is a better choice because Python does not use the term
parameter.
append To add an element to an existing list. In Python, append () is a method that will pass
an object into an existing list.
arithmetic operator A symbol in code that tells a computer to perform a specific math operation, such as
addition, subtraction, multiplication, or division. (+ ¬¬¬- × / ).
array A type of data structure that can store a fixed number of elements, as long as they
are all the same data type. Arrays are a lot like lists.
artificial intelligence (AI) Any program that analyzes its environment and is able to respond accordingly to
achieve an end goal.
assignment A statement that sets or stores a value in a variable.
, assignment operator A symbol in code that assigns values from the right side of an equation (called an
operand) to what is on the left side of the equation. Assigning a value to a variable
is a classic example that uses the "equal to" assignment operator. (Example: color =
255).
authenticate To verify a user's identity.
backlog A sequential and prioritized list of what needs to be done to create the app the user
wants. The list can be technical requirements or user centric in the form of user
stories.
bash A command processor that typically runs in a text window. Bash is a text-based way
to manipulate a computer's file structure and execute commands. Bash can also
read commands from a file, called a script. In Cloud9, it is also called the Python
Interactive Interpreter. (Bourne Again Shell)
best-so-far loop A piece of code (loop) that contains a variable which stores the "best" value as
defined by the programmer. Each time the code executes the loop, the program
evaluates whether it finds a "better" value as defined by the programmer. If it finds
one that is better, then it replaces that variable value with the new value and
continues until it reaches the end of the list.
block `Any sequence of statements in Python that occur at the same indentation level.
block-based programming language A means to create computer programs by manipulating elements graphically rather
than using text. Also called visual programming language.
blog Short for "wed log" it is a regularly updated website or web page, typically one run
by an individual or small group, that is written in an informal or conversational style.
A blog is a one-way form of communication on the web.
boolean algebra The basis of all modern computing, Boolean algebra is founded on the idea of
conditionals and base 2 mathematics. In Python, the Boolean data type has only
two possible conditions: True or False.
boolean expression A processing decision branch using comparison operators (= ≠ > <) that is defined
to return a Boolean value ("true" or "false"). By using Boolean expression to ask
questions, the program can determine what to do next.
boolean value One of two values, such as "true" or "false", that allows a computer to know what
step in the conditional statement process to execute next.
branch An alternative path through a program, often occurring as the result of the
evaluation of an expression in a conditional.
Essentials PLTW Terms
2026 | Key Terms, Study
Guide, Practice Questions,
Answers & Exam Review |
Complete Ethics Study
Guide
Updated 2026 Questions and Answers
100% Verified Exam Prep and Comprehensive
Rationales
Included
,abstraction A technique or process that manages complexity in a program or computer system.
Abstraction "hides" details or removes duplication, allowing the programmer to
focus on high-level considerations and functions rather than the rules of a
programming language.
accumulator A role that a variable may take on in which it keeps a running or cumulative total or
value. Commonly an accumulator is initialized outside of a loop, assigned new
values within the loop, and then its result is used outside of the loop.
aggregator A variable that adds together all the values or data at a specific moment.
algorithm A set of steps to accomplish a task. An algorithm can be expressed in many kinds of
notation, such as natural language, pseudocode, and flowcharts. Algorithms are
essential to the way computers process data, because they contain the specific
instructions for what a computer or program does.
API An application programming interface is a set of program routines, protocols, and
tools that facilitates communication with a client app that is designed specifically for
the server. A client computer program can send instructions to the server and get
data from the server through the API.
app A software application, especially one that a user downloads to a mobile device.
argument The values that a program provides to a function or subroutine. Sometimes coding
professionals use the terms "argument" and "parameter" interchangeably. In this
course, argument is a better choice because Python does not use the term
parameter.
append To add an element to an existing list. In Python, append () is a method that will pass
an object into an existing list.
arithmetic operator A symbol in code that tells a computer to perform a specific math operation, such as
addition, subtraction, multiplication, or division. (+ ¬¬¬- × / ).
array A type of data structure that can store a fixed number of elements, as long as they
are all the same data type. Arrays are a lot like lists.
artificial intelligence (AI) Any program that analyzes its environment and is able to respond accordingly to
achieve an end goal.
assignment A statement that sets or stores a value in a variable.
, assignment operator A symbol in code that assigns values from the right side of an equation (called an
operand) to what is on the left side of the equation. Assigning a value to a variable
is a classic example that uses the "equal to" assignment operator. (Example: color =
255).
authenticate To verify a user's identity.
backlog A sequential and prioritized list of what needs to be done to create the app the user
wants. The list can be technical requirements or user centric in the form of user
stories.
bash A command processor that typically runs in a text window. Bash is a text-based way
to manipulate a computer's file structure and execute commands. Bash can also
read commands from a file, called a script. In Cloud9, it is also called the Python
Interactive Interpreter. (Bourne Again Shell)
best-so-far loop A piece of code (loop) that contains a variable which stores the "best" value as
defined by the programmer. Each time the code executes the loop, the program
evaluates whether it finds a "better" value as defined by the programmer. If it finds
one that is better, then it replaces that variable value with the new value and
continues until it reaches the end of the list.
block `Any sequence of statements in Python that occur at the same indentation level.
block-based programming language A means to create computer programs by manipulating elements graphically rather
than using text. Also called visual programming language.
blog Short for "wed log" it is a regularly updated website or web page, typically one run
by an individual or small group, that is written in an informal or conversational style.
A blog is a one-way form of communication on the web.
boolean algebra The basis of all modern computing, Boolean algebra is founded on the idea of
conditionals and base 2 mathematics. In Python, the Boolean data type has only
two possible conditions: True or False.
boolean expression A processing decision branch using comparison operators (= ≠ > <) that is defined
to return a Boolean value ("true" or "false"). By using Boolean expression to ask
questions, the program can determine what to do next.
boolean value One of two values, such as "true" or "false", that allows a computer to know what
step in the conditional statement process to execute next.
branch An alternative path through a program, often occurring as the result of the
evaluation of an expression in a conditional.
