pollen grain

This term refers to the individual microscopic unit of pollen. While "pollen" is used as an uncountable mass noun to describe the powdery substance in bulk, "pollen grain" is the specific countable unit used in scientific, botanical, or forensic contexts to describe a single spore.

In technical writing, the term is often associated with morphology and palynology, where the unique shape and surface texture of a single grain are used to identify plant species or date geological layers.