What prefix indicates "half" or "partial"?

The prefix that indicates "half" or "partial" is "semi-." This prefix is derived from Latin, where it means "half." It is commonly used in medical terminology and other fields to denote something that is not complete but rather a part of something larger or a reduced version. For example, "semicircle" refers to half of a circle.

While "hemi-" also denotes half, it is derived from Greek and is used in specific contexts, particularly in medical terminology (such as "hemisphere," meaning half of a sphere, often used in reference to the brain). However, "semi-" is the more universally recognized prefix for indicating partiality in broader contexts.

The other prefixes, such as "mono-," indicate singularity or one, and do not imply anything about being half or partial, which further clarifies that "semi-" is indeed the correct choice for this question.