Noun, pl. pollens
1. A fine to coarse powder containing the microgametophytes of seed plants, which produce the male gametes (sperm cells). Pollen grains have a hard coat that protects the sperm cells during the process of their movement from the stamens to the pistil of flowering plants or from the male cone to the female cone of coniferous plants. (wikipedia.org)
2. A fine powdery substance, typically yellow, consisting of microscopic grains discharged from the male part of a flower or from a male cone. Each grain contains a male gamete that can fertilize the female ovule, to which pollen is transported by the wind, insects, or other animals. (Google Dictionary)
3. The microspores of seed plants, the powdery mass of microspores shed from anthers (biology-online.org); a mass of microspores in a seed plant appearing usually as a fine dust (merriam-webster.com).
4. The fine spores that contain male gametes and that are borne by an anther in a flowering plant (wordnetweb.princeton.edu).
5. A dusty bloom on the body of an insect (merriam-webster.com).
Word origin: From Latin pollen “mill dust; fine flour,” related to polenta “peeled barley,” and pulvis “dust.”