What is meant by truncation error?

Truncation error generally refers to the phenomenon that occurs when a numerical result is approximated by cutting off or "truncating" a value, leading to a loss of precision. In the context of programming and numerical methods, truncation can happen when a number is rounded off to a certain number of decimal places or when a function does not retain all relevant information due to limits on its representation.

Choosing the option that states data is being "accidentally cut off" directly aligns with the idea of truncation. When calculations are performed, particularly in floating-point arithmetic, values can be shortened, which means that some precision is intentionally or accidentally lost as the value is modified.

The other options refer to different kinds of issues in programming. Inaccurate recalculation could hint at rounding errors but does not specifically describe truncation. Improper formatting pertains to how data is presented rather than is concerned with the precision of its numerical value. Lastly, data exceeding system capacity involves overflow situations rather than error resulting from truncation. Thus, the definition best summarizing truncation error is accurately conveyed by saying it involves data being cut off.