Final answer:
A misstroke of a key is an error made while typing. Variation between source copy and displayed or printed copy can occur due to formatting or other reasons. Departure from acceptable format refers to not meeting formatting guidelines.
Step-by-step explanation:
A misstroke of a key refers to an error made when pressing a key on a keyboard. It can occur when you accidentally press the wrong key or when you press a key multiple times by mistake. For example, typing 'teh' instead of 'the' is a misstroke.
A variation between the source copy and the displayed or printed copy can happen due to various reasons, such as formatting issues, encoding errors, or differences in software and hardware. These variations can lead to discrepancies in the appearance or content of the text.
Departure from acceptable format refers to not following the prescribed formatting guidelines.