margin of error

This term functions as a compound noun and is primarily used in technical, statistical, or high-stakes professional contexts. In statistics, it describes the precision of a sample estimate, whereas in general planning, it describes a safety buffer. It carries a connotation of risk management and precision.

Because it is a compound noun, it is typically treated as a singular unit. While the word "margin" can be pluralized in other contexts, this specific phrase is almost exclusively used in the singular to describe a specific threshold or allowance for inaccuracy.