| herald patch | The initial rapidly enlarging oval-shaped red papulosquamous lesion, usually on the trunk, heralding the widespread eruption of pityriasis rosea, and preceding the latter by 7-14 days. (05 Mar 2000) |
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| herapathite | <chemistry> The sulphate of iodoquinine, a substance crystallizing in thin plates remarkable for their effects in polarizing light. Origin: Named after Dr. Herapath, the discoverer. Source: Websters Dictionary (01 Mar 1998) |
| herb | <botany> Any vascular plant that never produces a woody stem. Compare: forb. (09 Oct 1997) |
| herb-woman | A woman that sells herbs. Source: Websters Dictionary (01 Mar 1998) |
| herbaceous | <botany> Refers to a plant that has a non-woody stem and which dies back at the endof the growing season. (09 Oct 1997) |
| herbage | <botany> Herbs collectively, the green foliage and juicy stems of herbs. (09 Oct 1997) |
| herbal | 1. A book containing the names and descriptions of plants. 2. A collection of specimens of plants, dried and preserved; a hortus siccus; an herbarium. Source: Websters Dictionary (01 Mar 1998) |
| herbalist | One skilled in the knowledge of plants; a collector of, or dealer in, herbs, especially medicinal herbs. Source: Websters Dictionary (01 Mar 1998) |
| herbals | Books on herbs or plants usually describing their medicinal value. (12 Dec 1998) |
| herbarium | Origin: LL, fr. L. Herba. See Herb, and cf. Arbor, Herbary. 1. A collection of dried specimens of plants, systematically arranged. 2. A book or case for preserving dried plants. Source: Websters Dictionary (01 Mar 1998) |
| Herbert | Herbert, English ophthalmic surgeon, 1865-1942. (05 Mar 2000) |
| herbicide | <chemical> A chemical used to kill or control the growth of plants. Some herbicides (such as synthetic auxins and triazine) selectively kill broad-leaved plants while leaving grass-leaved plants (i.e., cereal crops) unharmed. Other herbicides, such as paraquat, kill all plants. Herbicide use has dramatically increased crop yield worldwide but has caused serious environmental problems, polluting soil and water and causing health hazards for humans and animals. See: pesticide. (09 Oct 1997) |
| herbicides | Pesticides used to destroy unwanted vegetation, especially various types of weeds, grasses, and woody plants. (12 Dec 1998) |
| herbicides, carbamate | Herbicides which owe their activity to the carbamate moiety in the molecule. (12 Dec 1998) |
| herbicides, triazine | Herbicides which owe their activity to the triazine moiety in the molecule. (12 Dec 1998) |