| HORNYHEADS | • hornyheads n. Plural of hornyhead. • HORNYHEAD n. a North American river chub. |
| HOYDENHOOD | • hoydenhood n. (Archaic, rare) The time or state of being a hoyden. • HOYDENHOOD n. the state of being a hoyden. |
| HYDATHODES | • hydathodes n. Plural of hydathode. • HYDATHODE n. an epidermal water-excreting organ. |
| HYDROCHORE | • hydrochore n. A plant whose spores, seeds, or fruits are dispersed by water. • HYDROCHORE n. a plant disseminated by water. |
| HYDROGRAPH | • hydrograph n. A graph of flow past a point in a river versus time. • hydrograph n. A graph of water table versus time. • HYDROGRAPH n. a graph of variation of stream flow over time. |
| HYDROPATHS | • hydropaths n. Plural of hydropath. • HYDROPATH n. a practitioner of hydropathy, the study of treating diseases with water. |
| HYDROPATHY | • hydropathy n. The therapeutic use of water, either internally or externally. • HYDROPATHY n. the study of treating diseases with water. |
| HYDROPHANE | • hydrophane n. (Mineralogy) A semitranslucent variety of opal that becomes translucent or transparent on immersion in water. • HYDROPHANE n. a semitranslucent variety of opal that becomes translucent or transparent on immersion in water. |
| HYDROPHILE | • hydrophile n. (Chemistry) Any hydrophilic substance. • hydrophile n. (Zoology) Any organism that thrives in the presence of water. • hydrophile adj. Hydrophilic. |
| HYDROPHILY | • hydrophily n. A form of pollination whereby pollen is distributed by the flow of waters, particularly in rivers and streams. • HYDROPHILY n. an affinity for water. |
| HYDROPHONE | • hydrophone n. A transducer that converts underwater sound waves into electrical signals, rather like a microphone. • HYDROPHONE n. an apparatus for listening to sounds conveyed by water. |
| HYDROPHYTE | • hydrophyte n. (Botany) A plant that lives in or requires an abundance of water, usually excluding seaweed. • HYDROPHYTE n. an aquatic plant; an alga. |
| HYDROTHECA | • hydrotheca n. (Zoology) One of the calicles that protect the hydranths in certain Hydroidea (Thecaphora). • HYDROTHECA n. the horny cup of a hydranth. |
| ICHTHYOIDS | • ichthyoids n. Plural of ichthyoid. • ICHTHYOID n. any fishlike creature. |
| YOUTHHEADS | • YOUTHHEAD n. (obsolete) youth, also YOUNGTH, YOUTHHOOD. |
| YOUTHHOODS | • youthhoods n. Plural of youthhood. • YOUTHHOOD n. (obsolete) youth, also YOUNGTH, YOUTHHEAD. |