13-letter words starting with h
- hecate strait — a strait in central British Columbia, Canada, between the mainland and the Queen Charlotte Islands. 160 miles (257 km) long and 40–80 miles (64–129 km) wide.
- hedge sparrow — the dunnock.
- hedge trimmer — garden tool for cutting hedges
- hefner candle — a German unit of luminous intensity, equal to 0.92 of a candela.
- heilong jiang — Amur.
- heir apparent — an heir whose right is indefeasible, provided he or she survives the ancestor.
- helen of troy — Also called Helen of Troy. Classical Mythology. the beautiful daughter of Zeus and Leda and wife of Menelaus whose abduction by Paris was the cause of the Trojan War.
- heli-boarding — the sport of snowboarding on mountains or glaciers accessible only by helicopter or skiplane
- helianthemums — Plural form of helianthemum.
- helianthine b — methyl orange.
- helicoid cyme — an inflorescence, or cyme, in which each flowering branch gives rise to one lateral branch that is coiled snail-like and then expanded.
- heliocentrism — The theory that the sun is the center of the universe, (This theory is historically important and was widely accepted at the time of Copernicus, Galileo and Kepler.).
- heliographing — Present participle of heliograph.
- heliotropical — heliotropic
- helispherical — spiral
- hell on earth — torment, horrendous experience
- hellenization — to make Greek in character.
- hellgrammites — Plural form of hellgrammite (Alternative spelling of hellgramites).
- helminthiasis — a disease caused by parasitic worms in the intestines.
- helminthology — the scientific study of worms, especially of parasitic worms.
- help off with — If you help someone off with an item of clothing, you help them take it off.
- helper t cell — a T cell that stimulates B cells to produce antibody against a foreign substance, using lymphokines or direct contact as a signal.
- helper t-cell — a type of T cell that helps coordinate the immune response, especially by activating B cells: the AIDS virus targets and destroys these T cells
- hemacytometer — hemocytometer.
- hemagglutinin — A substance, such as a viral protein, that causes hemagglutination.
- hematogenesis — hematopoiesis.
- hematological — Hematologic.
- hematologists — Plural form of hematologist.
- hematophagous — feeding on blood, as the vampire bat.
- hematopoiesis — the formation of blood.
- hematopoietic — the formation of blood.
- hematosalpinx — (medicine) A medical condition involving bleeding into the Fallopian tubes.
- hematothermal — warm-blooded; homoiothermal.
- hemicellulose — any of a group of gummy polysaccharides, intermediate in complexity between sugar and cellulose, that hydrolyze to monosaccharides more readily than cellulose.
- hemichordates — Plural form of hemichordate.
- hemicolectomy — (surgery) A colectomy involving the removal of only the ascending (right) colon or the descending (left) colon.
- hemimetabolic — (zoology) Having an incomplete metamorphosis, the larvae differing from the adults chiefly in lacking wings.
- hemiparasitic — Semiparasitic.
- hemispherical — having the form of a hemisphere.
- hemiterpenoid — (chemistry) a terpenoid having a C5 skeleton.
- hemocytoblast — a primordial cell capable of developing into any type of blood cell.
- hemocytometer — an instrument for counting blood cells.
- hemolymphatic — a fluid in the body cavities and tissues of invertebrates, in arthropods functioning as blood and in some other invertebrates functioning as lymph.
- hemp agrimony — a European composite plant, Eupatorium cannabinum, having dull purplish flowers.
- henceforwards — (archaic) henceforth, from this point onwards.
- hendecahedron — a solid figure having 11 faces.
- heortological — of or relating to heortology
- hepatectomies — Plural form of hepatectomy.
- hepatobiliary — Of, pertaining to, or originating in the liver, bile ducts and gallbladder.
- hepatojugular — (medicine) Relating to the liver and the jugular vein.