| valve-shell | <zoology> Any fresh water gastropod of the genus Valvata. Source: Websters Dictionary (01 Mar 1998) |
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| mail-shell | <zoology> A chiton. Source: Websters Dictionary (01 Mar 1998) |
| mask shell | <zoology> Any spiral marine shell of the genus Persona, having a curiously twisted aperture. Source: Websters Dictionary (01 Mar 1998) |
| goroon shell | <zoology> A large, handsome, marine, univalve shell (Triton femorale). Source: Websters Dictionary (01 Mar 1998) |
| rice-shell | <zoology> Any one of numerous species of small white polished marine shells of the genus Olivella. Source: Websters Dictionary (01 Mar 1998) |
| wedge-shell | <zoology> Any one of numerous species of small marine bivalves belonging to Donax and allied genera in which the shell is wedge-shaped. Source: Websters Dictionary (01 Mar 1998) |
| wing-shell | <zoology> Any one of various species of marine bivalve shells belonging to the genus Avicula, in which the hinge border projects like a wing. Any marine gastropod shell of the genus Strombus. See Strombus. Any pteropod shell. Source: Websters Dictionary (01 Mar 1998) |
| worm-shell | <zoology> Any species of Vermetus. Source: Websters Dictionary (01 Mar 1998) |
| wreath-shell | <zoology> A marine shell of the genus Turbo. See Turbo. Source: Websters Dictionary (01 Mar 1998) |
| pouch-shell | <zoology> A small British and American pond snail (Bulinus hypnorum). Source: Websters Dictionary (01 Mar 1998) |
| cytotrophoblastic shell | The external layer of foetally derived trophoblastic cells on the maternal surface of the placenta. (05 Mar 2000) |
| shell | 1. A hard outside covering, as of a fruit or an animal. Specifically: The covering, or outside part, of a nut; as, a hazelnut shell. A pod. The hard covering of an egg. "Think him as a serpent's egg, . . . And kill him in the shell. <mathematics> " (Shak) Hence, by extension, any mollusks having such a covering. 2. A hollow projectile, of various shapes, adapted for a mortar or a cannon, and containing an explosive substance, ignited with a fuse or by percussion, by means of which the projectile is burst and its fragments scattered. See Bomb. 3. The case which holds the powder, or charge of powder and shot, used with breechloading small arms. 4. Any slight hollow structure; a framework, or exterior structure, regarded as not complete or filled in; as, the shell of a house. 5. A coarse kind of coffin; also, a thin interior coffin inclosed in a more substantial one. 6. An instrument of music, as a lyre, the first lyre having been made, it is said, by drawing strings over a tortoise shell. "When Jubal struck the chorded shell." (Dryden) 7. An engraved copper roller used in print works. 8. The husks of cacao seeds, a decoction of which is often used as a substitute for chocolate, cocoa, etc. 9. The outer frame or case of a block within which the sheaves revolve. 10. A light boat the frame of which is covered with thin wood or with paper; as, a racing shell. Message shell, a bombshell inside of which papers may be put, in order to convey messages. Shell bit, a tool shaped like a gouge, used with a brace in boring wood. See Bit. Shell button. A button made of shell. A hollow button made of two pieces, as of metal, one for the front and the other for the back, often covered with cloth, silk, etc. Shell cameo, a cameo cut in shell instead of stone. Shell flower. <botany> A kind of marl characterised by an abundance of shells, or fragments of shells. Shell meat, food consisting of shellfish, or testaceous mollusks. Shell mound. See Mound. Shell of a boiler, the exterior of a steam boiler, forming a case to contain the water and steam, often inclosing also flues and the furnace; the barrel of a cylindrical, or locomotive, boiler. Shell road, a road of which the surface or bed is made of shells, as oyster shells. Shell sand, minute fragments of shells constituting a considerable part of the seabeach in some places. Origin: OE. Shelle, schelle, AS. Scell, scyll; akin to D. Shel, Icel. Skel, Goth. Skalja a tile, and E. Skill. Cf. Scale of fishes, Shale, Skill. Source: Websters Dictionary (01 Mar 1998) |
| shell nail | Bronchiectasis with excessive longitudinal curvature of the nail plate and atrophy of the nail bed and underlying bone. (05 Mar 2000) |
| shell shock | The World War I name for what is known today as posttraumatic stress, this is a psychological disorder that develops in some individuals who have had major traumatic experiences (and, for example, have been in a serious accident or through a war). The person is typically numb at first but later has symptoms including depression, excessive irritability, guilt (for having survived while others died), recurrent nightmares, flashbacks to the traumatic scene, and overreactions to sudden noises. Posttraumatic stress became known as such in the 70s due to the adjustment problems of some vietnam veterans. (12 Dec 1998) |
| shock, shell | The World War I name for what is known today as posttraumatic stress, this is a psychological disorder that develops in some individuals who have had major traumatic experiences (and, for example, have been in a serious accident or through a war). The person is typically numb at first but later has symptoms including depression, excessive irritability, guilt (for having survived while others died), recurrent nightmares, flashbacks to the traumatic scene, and overreactions to sudden noises. Posttraumatic stress became known as such in the 70s due to the adjustment problems of some vietnam veterans.shots, allergy: known medically as allergy desensitization or allergy immunotherapy, the injections are designed to stimulate the immune system with gradually increasing doses of the substances to which a person is allergic, the aim being to modify or stop the allergy war (by reducing the strength of the IgE and its effect on the mast cells). This form of treatment is very effective for allergies to pollen, mites, cats, and especially stinging insects (e.g., bees, hornets, yellowjackets, wasps, velvet ants, fire ants). Allergy immunotherapy usually takes 6 months to a year to become effective and injections are usually required for 3-5 years. (12 Dec 1998) |