QR codes might seem like just a random pattern of squares, but they are actually made up of several key components, each with its own function. Here are some of the parts and terms used to describe them.

Key Components / Vocabulary of a QR Code

• Position Markers: The three large squares in the corners of the QR code that help the scanner detect the code’s orientation.
• Alignment Markers: Smaller squares that help the scanner correct for distortion.
• Timing Patterns: A series of alternating black and white modules that help the scanner determine the size of the data matrix.
• Version Information: Data that indicates the version of the QR code, which corresponds to the amount of data it can store.
• Format Information: Information about the error correction level and the mask pattern used in the QR code.
• Data Area: The seemingly random black modules spread throughout the QR code - this is encoded data using a specific patented format data is typically in alphanumeric characters and most frequently it is a URL.
• Error Correction Blocks: Parts of the QR code that allow it to be read even if it is partially damaged or obscured.
• Error Correction Level: A feature that determines how much of the QR code can be restored if it becomes damaged. The error correction level affects both the amount of recoverable data and the total data storage capacity of the QR code. 

Position Markers
Position markers are the three large squares located in the corners of the QR code. These markers help the QR code scanner determine the orientation of the code, ensuring that it can be read correctly regardless of the angle at which it is scanned.

Alignment Markers
Alignment markers are smaller squares that appear in certain versions of QR codes, especially those that store more data. These markers help correct distortion that might occur when the QR code is printed on a curved or uneven surface.

Timing Patterns
Timing patterns are alternating black and white modules that run between the position markers. These patterns help the scanner determine the size of the data matrix and ensure that the code is read accurately.

Version Information
Each QR code version can store a different amount of data, and the version information is encoded in the QR code to indicate this. This information helps the scanner understand how much data is in the code and how to process it.

Format Information
The format information in a QR code includes data about the error correction level and the mask pattern used. This helps the scanner correctly interpret the data even if the QR code is damaged or if parts of it are obscured.

Data Area
The data area is the main part of the QR code that holds the actual information—such as a URL, contact details, or Wi-Fi login credentials. This is the part that the scanner decodes to provide you with the information or action linked to the QR code.

Error Correction Blocks
QR codes include error correction blocks that allow them to be read even if they are partially damaged or obscured. The amount of damage a QR code can withstand depends on the error correction level selected during its creation. There are four levels of error correction:

• L (Low): Can correct up to 7% damage, allowing for maximum data storage.
• M (Medium): Can correct up to 15% damage, balancing data storage and error correction.
• Q (Quartile): Can correct up to 25% damage, offering protection against moderate damage.
• H (High): Can correct up to 30% damage, providing the highest level of error correction but reducing data capacity.

The higher the error correction level, the more damage the QR code can tolerate while remaining scannable, though this reduces the amount of data that can be stored.