| horizontal |
parallel to the horizon or to the earth; ninety degrees from vertical. |
| horizontal union |
see "craft union." |
| hormone |
any of various substances secreted by the cells of the body that circulate in the bloodstream and produce specific, usu. stimulating effects in certain receptive organs or tissues. [2 definitions] |
| horn |
the hard, bony, hollow growths that extend, usu. in a pair, from the head of certain mammals such as cows and deer. [6 definitions] |
| hornbeam |
any of various shrubs or trees of the birch family having hard white wood covered by smooth gray bark, or the wood of this plant. |
| hornbill |
any of several tropical birds having a large curved bill, usu. with a horny bulge. |
| hornblende |
a variety of amphibole that is greenish to black in color, common in metamorphic rocks and dark igneous rocks that are rich in iron and magnesium. |
| hornbook |
formerly, a child's primer for reading or math, consisting of a page of material covered by a transparent sheet of horn and framed. [2 definitions] |
| horned lizard |
see "horned toad." |
| horned owl |
any of several owls having earlike tufts of feathers, esp. the great horned owl. |
| horned pout |
a common bullhead catfish, esp. the brown bullhead. |
| horned toad |
any of several insect-eating lizards of western North America and Mexico, having spiny scales covering the body and hornlike spines on the head. |
| horned viper |
a highly poisonous snake of Africa, having a hornlike protrusion above each eye; asp. |
| hornet |
any of several large stinging insects that live in colonies and build large, round, papery nests; wasp. |
| hornless |
combined form of horn. |
| horn of plenty |
see "cornucopia." |
| hornpipe |
a musical wind instrument whose mouthpiece and bell are usu. made of ox horn. [3 definitions] |
| hornworm |
the caterpillar of any of several hawk moths, which has a thornlike projection on the rear segment. |
| hornwort |
any of several aquatic plants that have whorled leaves and unisexual flowers. |
| horny |
having horns or hornlike projections. [4 definitions] |
| horologe |
any device used for keeping time, such as a sundial or clock. |