| Placido da Costa, Antonio | <person> Portuguese ophthalmologist, 1848-1916. See: Placido da Costa's disk. (05 Mar 2000) |
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| placket | 1. A petticoat, especially. An under petticoat; hence, a cant term for a woman. 2. The opening or slit left in a petticoat or skirt for convenience in putting it on. Synonym: placket hole. 3. A woman's pocket. Origin: F. Plaquer to lay or clap on. See Placard. Source: Websters Dictionary (01 Mar 1998) |
| placode | <embryology> Area of thickened ectoderm in the embryo from which a nerve ganglion or a sense organ will develop. (31 Dec 1997) |
| placoderm | <paleontology> One of the Placodermi. Origin: Gr, tablet + skin. Source: Websters Dictionary (01 Mar 1998) |
| placodermal | <paleontology> Of or pertaining to the placoderms; like the placoderms. Source: Websters Dictionary (01 Mar 1998) |
| placodermata | <paleontology> Same as Placodermi. Source: Websters Dictionary (01 Mar 1998) |
| placodermi | <paleontology> An extinct group of fishes, supposed to be ganoids. The body and head were covered with large bony plates. Origin: NL, fr. Gr, a tablet + skin. Source: Websters Dictionary (01 Mar 1998) |
| placoganoid | <zoology> Pertaining to the Placoganoidei. Source: Websters Dictionary (01 Mar 1998) |
| placoganoidei | <zoology> A division of ganoid fishes including those that have large external bony plates and a cartilaginous skeleton. Origin: NL, fr. Gr, a tablet + NL. Ganoidei. See Ganoidei. Source: Websters Dictionary (01 Mar 1998) |
| placoid | <zoology> Platelike; having irregular, platelike, bony scales, often bearing spines; pertaining to the placoids. Origin: Gr, a tablet. <zoology> Any fish having placoid scales, as the sharks. One of the Placoides. Source: Websters Dictionary (01 Mar 1998) |
| placoides | <zoology> A group of fishes including the sharks and rays; the Elasmobranchii. Synonym: Placoidei. Source: Websters Dictionary (01 Mar 1998) |
| placoidian | <zoology> One of the placoids. Source: Websters Dictionary (01 Mar 1998) |
| placophora | <zoology> A division of gastropod Mollusca, including the chitons. The back is covered by eight shelly plates. Synonym: Polyplacophora. Origin: NL, from Gr, tablet + to bear. Source: Websters Dictionary (01 Mar 1998) |
| pladaroma | Pladarosis A soft wartlike growth on the eyelid. Origin: G. Pladaros, wet, damp, flaccid, + -oma, tumour (05 Mar 2000) |
| plafond | A ceiling, especially the ceiling of the ankle joint, i.e., the articular surface of the distal end of the tibia. Origin: Fr. Ceiling (05 Mar 2000) |