Perimorph Per"i·morph noun [ Prefix peri- + Greek ... form.] (Min.) A crystal of one species inclosing one of another species. See Endomorph .

Perimysial Per`i·my"sial adjective (Anat.) (a) Surrounding a muscle or muscles. (b) Of or pertaining to the perimysium.

Perimysium Per`i·my"si·um noun [ New Latin , from Greek ... about + ... muscle.] (Anat.) The connective tissue sheath which surrounds a muscle, and sends partitions inwards between the bundles of muscular fibers.

Perineal Per`i·ne"al adjective (Anat.) Of or pertaining to the perineum.

Perineoplasty Per`i·ne"o·plas`ty noun [ Perineum + -plasty .] (Medicine) The act or process of restoring an injured perineum.

Perineorrhaphy Per`i·ne·or"rha·phy noun [ Perineum + Greek ... to sew.] (Medicine) The operation of sewing up a ruptured perineum.

Perinephritis Per`i·ne·phri"tis noun [ New Latin See Peri- , and Nephritis .] (Medicine) Inflammation of the cellular tissue around the kidney. -- Per`i*ne*phrit"ic , adjective

Perineum Per`i·ne"um noun [ New Latin , from Greek ..., ....] (Anat.) The region which is included within the outlet of the pelvis, and is traversed by the urinogenital canal and the rectum.

Perineurial Per`i·neu"ri·al adjective (Anat.) Surrounding nerves or nerve fibers; of or pertaining to the perineurium.

Perineurium Per`i·neu"ri·um noun [ New Latin , from Greek ... about + ... a nerve.] (Anat.) The connective tissue sheath which surrounds a bundle of nerve fibers. See Epineurium , and Neurilemma .

Perinuclear Per`i·nu"cle·ar adjective (Biol.) Of or pertaining to a nucleus; situated around a nucleus; as, the perinuclear protoplasm.

Perinæum Per`i·næ"um noun See Perineum .

Period Pe"ri·od noun [ Latin periodus , Greek ... a going round, a way round, a circumference, a period of time; ... round, about + ... a way: confer French période .] 1. A portion of time as limited and determined by some recurring phenomenon, as by the completion of a revolution of one of the heavenly bodies; a division of time, as a series of years, months, or days, in which something is completed, and ready to recommence and go on in the same order; as, the period of the sun, or the earth, or a comet. 2. Hence: A stated and recurring interval of time; more generally, an interval of time specified or left indefinite; a certain series of years, months, days, or the like; a time; a cycle; an age; an epoch; as, the period of the Roman republic.

How by art to make plants more lasting than their ordinary period .

Bacon. 3. (Geol.) One of the great divisions of geological time; as, the Tertiary period ; the Glacial period . See the Chart of Geology . 4. The termination or completion of a revolution, cycle, series of events, single event, or act; hence, a limit; a bound; an end; a conclusion. Bacon.

So spake the archangel Michael; then paused,
As at the world's great period .

Milton.

Evils which shall never end till eternity hath a period .

Jer. Taylor.

This is the period of my ambition.

Shak. 5. (Rhet.) A complete sentence, from one full stop to another; esp., a well-proportioned, harmonious sentence. "Devolved his rounded periods ." Tennyson.

Periods are beautiful when they are not too long.

B. Johnson. » The period , according to Heyse, is a compound sentence consisting of a protasis and apodosis; according to Becker, it is the appropriate form for the coördinate propositions related by antithesis or causality. Gibbs. 6. (Print.) The punctuation point [ .] that marks the end of a complete sentence, or of an abbreviated word. 7. (Math.) One of several similar sets of figures or terms usually marked by points or commas placed at regular intervals, as in numeration, in the extraction of roots, and in circulating decimals. 8. (Medicine) The time of the exacerbation and remission of a disease, or of the paroxysm and intermission. 9. (Mus.) A complete musical sentence. The period , the present or current time, as distinguished from all other times. Syn. -- Time; date; epoch; era; age; duration; limit; bound; end; conclusion; determination.

Period Pe"ri·od transitive verb To put an end to. [ Obsolete] Shak.

Period Pe"ri·od intransitive verb To come to a period; to conclude. [ Obsolete] "You may period upon this, that," etc. Felthman.

Periodate Per·i"o·date noun (Chemistry) A salt of periodic acid.

Periodic Per`i·od"ic adjective [ Prefix per- + iodic .] (Chemistry) Pertaining to, derived from, or designating, the highest oxygen acid (HIO...) of iodine.

Periodic, Periodical Pe`ri·od"ic, Pe`ri·od"ic·al adjective [ Latin periodicus , Greek ...: confer French périodique .] 1. Of or pertaining to a period or periods, or to division by periods.

The periodical times of all the satellites.

Sir J. Herschel. 2. Performed in a period, or regular revolution; proceeding in a series of successive circuits; as, the periodical motion of the planets round the sun. 3. Happening, by revolution, at a stated time; returning regularly, after a certain period of time; acting, happening, or appearing, at fixed intervals; recurring; as, periodical epidemics.

The periodic return of a plant's flowering.

Henslow.

To influence opinion through the periodical press.

Courthope. 4. (Rhet.) Of or pertaining to a period; constituting a complete sentence. Periodic comet (Astron.) , a comet that moves about the sun in an elliptic orbit; a comet that has been seen at two of its approaches to the sun. -- Periodic function (Math.) , a function whose values recur at fixed intervals as the variable uniformly increases. The trigonomertic functions, as sin x , tan x , etc., are periodic functions. Exponential functions are also periodic, having an imaginary period, and the elliptic functions have not only a real but an imaginary period, and are hence called doubly periodic . -- Periodic law (Chemistry) , the generalization that the properties of the chemical elements are periodic functions of their atomic wieghts. "In other words, if the elements are grouped in the order of their atomic weights, it will be found that nearly the same properties recur periodically throughout the entire series." The following tabular arrangement of the atomic weights shows the regular recurrence of groups (under I., II., III., IV., etc.), each consisting of members of the same natural family. The gaps in the table indicate the probable existence of unknown elements.

Periodical Pe`ri·od"ic·al noun A magazine or other publication which appears at stated or regular intervals.

Periodicalist Pe`ri·od"ic·al·ist noun One who publishes, or writes for, a periodical.

Periodically Pe`ri·od"ic·al·ly adverb In a periodical manner.

Periodicalness Pe`ri·od"ic·al·ness noun Periodicity.

Periodicity Pe`ri·o·dic"i·ty noun ; plural Periodicities . [ Confer French périodicité .] The quality or state of being periodical, or regularly recurrent; as, the periodicity in the vital phenomena of plants. Henfrey.

Periodide Per·i"o·dide noun [ Prefix per- + iodide .] An iodide containing a higher proportion of iodine than any other iodide of the same substance or series.

Periodontal Per`i·o·don"tal adjective [ Prefix peri- + Greek ..., ..., tooth.] (Anat.) Surrounding the teeth.

Periodoscope Pe`ri·od"o·scope noun [ Period + -scope .] (Medicine) A table or other means for calculating the periodical functions of women. Dunglison.

Periople Per"i·o·ple noun [ French périople , from Greek ... about + ... the hoof of a horse.] (Anat.) The external smooth horny layer of the hoof of the horse and allied animals.

Perioplic Per`i·op"lic adjective (Anat.) Of or pertaining to the periople; connected with the periople.

Periosteal Per`i·os"te·al adjective (Anat.) Situated around bone; of or pertaining to the periosteum.

Periosteum Per`i·os"te·um noun [ New Latin , from Greek ... round the bones; ... around + ... a bone: confer Latin periosteon .] (Anat.) The membrane of fibrous connective tissue which closely invests all bones except at the articular surfaces.

Periostitis Per`i·os·ti"tis noun [ New Latin See Periosteum , and -itis .] (Medicine) Inflammation of the periosteum.

Periostracum Per`i·os"tra·cum noun ; plural Periostraca . [ New Latin , from Greek ... around + ... shell of a testacean.] (Zoology) A chitinous membrane covering the exterior of many shells; -- called also epidermis .

Periotic Per`i·o"tic adjective [ Prefix peri- + Greek ..., ..., the ear.] (Anat.) Surrounding, or pertaining to the region surrounding, the internal ear; as, the periotic capsule. -- noun A periotic bone.

Peripatecian Per`i·pa·te"cian noun A peripatetic. [ Obsolete]

Peripatetic Per`i·pa·tet"ic adjective [ Latin peripateticus , Greek ..., from ... to walk about; ... about + ... to walk: confer French péripatétique .] 1. Walking about; itinerant. 2. Of or pertaining to the philosophy taught by Aristotle (who gave his instructions while walking in the Lyceum at Athens), or to his followers. "The true peripatetic school." Howell.

Peripatetic Per`i·pa·tet"ic noun 1. One who walks about; a pedestrian; an itinerant. Tatler. 2. A disciple of Aristotle; an Aristotelian.

Peripatetical Per`i·pa·tet"ic·al adjective Peripatetic. [ R.] Hales.

Peripateticism Per`i·pa·tet"i·cism noun [ Confer French péripatétisme .] The doctrines or philosophical system of the peripatetics. See Peripatetic , noun , 2. Lond. Sat. Rev.

Peripatus Pe·rip"a·tus noun [ New Latin , from Greek ... a walking about.] (Zoology) A genus of lowly organized arthropods, found in South Africa, Australia, and tropical America. It constitutes the order Malacopoda.

Peripetalous Per`i·pet"al·ous adjective (Botany) Surrounding, or situated about, the petals.

Peripheral Pe·riph"er·al adjective 1. Of or pertaining to a periphery; constituting a periphery; peripheric. 2. (Anat.) External; away from the center; as, the peripheral portion of the nervous system.

Peripheric, Peripherical Per`i·pher"ic, Per`i·pher"ic·al adjective [ Confer French périphérique . See Periphery .] See Peripheral .

Periphery Pe·riph"er·y noun ; plural Peripheries . [ Latin peripheria , Greek ...; ... around + ... to bear, carry: confer French périphérie .] 1. The outside or superficial portions of a body; the surface. 2. (Geom.) The circumference of a circle, ellipse, or other figure.

Periphrase Per"i·phrase noun [ Latin periphrasis , Greek ..., from ... to think about, to be expressed periphrastically; ... + ... to speak: confer French périphrase . See Phrase .] (Rhet.) The use of more words than are necessary to express the idea; a roundabout, or indirect, way of speaking; circumlocution. "To describe by enigmatic periphrases ." De Quincey.

Periphrase Per"i·phrase transitive verb [ imperfect & past participle Periphrased ; present participle & verbal noun Periphrasing .] [ Confer French périphraser .] To express by periphrase or circumlocution.

Periphrase Per"i·phrase intransitive verb To use circumlocution.

Periphrasis Pe·riph"ra·sis noun ; plural Periphrases . [ Latin ] See Periphrase .

Periphrastic, Periphrastical Per`i·phras"tic, Per`i·phras"tic·al adjective [ Greek ...: confer French périphrastique .] Expressing, or expressed, in more words than are necessary; characterized by periphrase; circumlocutory. Periphrastic conjugation (Gram.) , a conjugation formed by the use of the simple verb with one or more auxiliaries.

Periphrastically Per`i·phras"tic·al·ly adverb With circumlocution.

Periplast Per"i·plast noun [ Prefix peri- + Greek ... to mold, form.] (Biol.) Same as Periblast . -- Per`i*plas"tic adjective Huxley.