| HYPERICINS | • hypericins n. Plural of hypericin. • HYPERICIN n. a compound with antidepressant properties, found in St John's wort. |
| HYPERICUMS | • hypericums n. Plural of hypericum. • HYPERICUM n. a herbaceous plant or shrub. |
| PERICARDIA | • pericardia n. Plural of pericardium. • PERICARDIUM n. a membranous sac containing the heart. |
| PERICARPIC | • pericarpic adj. (Botany) Of or relating to a pericarp. • PERICARPIC adj. relating to the pericarp, also PERICARPIAL. |
| PERICENTER | • pericenter n. (Astronomy) The peribaryon, the point of closest approach of an astronomical object in an elliptical… • PERICENTER n. the point in the path of a body revolving round a centre at which it is nearest to the centre, also PERICENTRE. |
| PERICENTRE | • pericentre n. Alternative spelling of pericenter. • PERICENTRE n. the point in the path of a body revolving round a centre at which it is nearest to the centre, also PERICENTER. |
| PERICLASES | • periclases n. Plural of periclase. • PERICLASE n. a naturally occurring magnesium oxide. |
| PERICLINAL | • periclinal adj. (Biology) Parallel to the surface of an organ. • periclinal adj. (Botany) Of a type of cell division in a layer of cells that occurs parallel to an adjacent layer of cells. • PERICLINAL adj. sloping downwards in all directions from a point. |
| PERICLINES | • periclines n. Plural of pericline. • PERICLINE n. a variety of albite occurring as large elongated white crystals. |
| PERICRANIA | • pericrania n. Plural of pericranium. • PERICRANIUM n. a membrane covering the skull. |
| PERICULOUS | • periculous adj. Dangerous, hazardous, perilous. • PERICULOUS adj. (obsolete) dangerous, also PARLOUS, PERILOUS, PERLOUS. |
| PERICYCLES | • pericycles n. Plural of pericycle. • PERICYCLE n. the outermost layer or layers of the central cylinder. |
| PERICYCLIC | • pericyclic adj. (Botany) Of or relating to a pericycle. • pericyclic adj. (Chemistry) Of or relating to a pericyclic reaction. • PERICYCLIC adj. relating to the pericycle, the outermost layer or layers of the central cylinder. |