hect/o, hecat hundred hectoliter – 100 liters; hectare – metric unit equaling 100 ares or 10,000 square meters; hectometer – 100 meters.

helic/o spiral, circular helicopter – an aircraft with horizontal rotating wing; helix – a spiral form; helicon – a circular tuba.

heli/o sun heliotropism – movement or growth in relating to the sun; heliograph – apparatus used to send message with the help of sunlight; helianthus – genus of plants including sunflowers.

hemi half, partial hemicycle – a semicircular structure; hemisphere – one half of the earth; hemistich – half a line of poetry.

hem/o/a blood hemorrhage – clotting of the blood; hemorrhoids – swelling of the blood vessels; hemoglobin – red blood particle.

hepa liver hepatitis – inflammation of the liver; hepatoma – a tumor of the liver; hepatotoxic – toxic and damaging to the liver.

hept/a seven heptagon – a shape with seven angles and seven sides; Heptateuch – the first seven books of the Old Testament; heptameter – a line of verse consisting of seven metrical feet.

herbi grass, plant herbicide – any chemical used to kill unwanted plants, etc.; herbivorous – plant-eating; herbal – relating to plants.

hetero different, other heterogeneous – made up of unrelated parts; heteronyms – words with same spelling but different meanings; heterodox – not conforming to traditional beliefs.

hex/a six hexagon – a shape with six angles/sides; hexameter – a verse measured in six; hexapod – having six legs.

histo tissue histology – study of the microscopic structure of tissues; histochemistry – study of the chemical constitution of cells and tissues.

homo, homeo like, alike, same homogeneous – of the same nature or kind; homonym – sounding alike; homeopath – a therapy that is based on treating “same with same”

hydr/o liquid, water hydrate – to add water to; hydrophobia – intense fear of water; hydroponics – growing plants in liquid nutrient solution; hydraulic – operated by force created by a liquid.

hygr/o moisture, humidity hygrometer – tool used to measure humidity; hygrograph – instrument for recording variations in atmospheric humidity.

hyper too much, over, excessive, beyond hyperactive – very restless; hypercritical – too critical; hypertension – above normal pressure.

hyp/o under hypoglycemia – an abnormally low level of sugar in the blood; hypothermia – abnormally low body temperature; hypothesis – a theory that is unproven but used under the assumption that it is true.