What's the difference between principal and roof?

Principal


Definition:

  • (a.) Highest in rank, authority, character, importance, or degree; most considerable or important; chief; main; as, the principal officers of a Government; the principal men of a state; the principal productions of a country; the principal arguments in a case.
  • (a.) Of or pertaining to a prince; princely.
  • (n.) A leader, chief, or head; one who takes the lead; one who acts independently, or who has controlling authority or influence; as, the principal of a faction, a school, a firm, etc.; -- distinguished from a subordinate, abettor, auxiliary, or assistant.
  • (n.) The chief actor in a crime, or an abettor who is present at it, -- as distinguished from an accessory.
  • (n.) A chief obligor, promisor, or debtor, -- as distinguished from a surety.
  • (n.) One who employs another to act for him, -- as distinguished from an agent.
  • (n.) A thing of chief or prime importance; something fundamental or especially conspicuous.
  • (n.) A capital sum of money, placed out at interest, due as a debt or used as a fund; -- so called in distinction from interest or profit.
  • (n.) The construction which gives shape and strength to a roof, -- generally a truss of timber or iron, but there are roofs with stone principals. Also, loosely, the most important member of a piece of framing.
  • (n.) In English organs the chief open metallic stop, an octave above the open diapason. On the manual it is four feet long, on the pedal eight feet. In Germany this term corresponds to the English open diapason.
  • (n.) A heirloom; a mortuary.
  • (n.) The first two long feathers of a hawk's wing.
  • (n.) One of turrets or pinnacles of waxwork and tapers with which the posts and center of a funeral hearse were formerly crowned.
  • (n.) A principal or essential point or rule; a principle.

Example Sentences:

  • (1) In addition to their involvement in thrombosis, activated platelets release growth factors, most notably a platelet-derived growth factor (PDGF) which may be the principal mediator of smooth muscle cell migration from the media into the intima and of smooth muscle cell proliferation in the intima as well as of vasoconstriction.
  • (2) While stereology is the principal technique, particularly in its application to the parenchyma, other compartments such as the airways and vasculature demand modifications or different methods altogether.
  • (3) Chromatography and immunoassays are the two principal techniques used in research and clinical laboratories for the measurement of drug concentrations in biological fluids.
  • (4) This paper reports, principally, the caries results of the first three surveys of 5, 12 and 5-year-olds undertaken at the end of 1987, 1988 and 1989, respectively.
  • (5) Rigidly fixing the pubic symphysis stiffened the model and resulted in principal stress patterns that did not reflect trabecular density or orientations as well as those of the deformable pubic symphysis model.
  • (6) The binding parameters indicate that the principal activating effect of UMP is not simply to increase the affinity of the enzyme for glucose.
  • (7) Mononuclear phagocytic cells from patients with either principal form of leprosy functioned similarly to normal monocytes in phagocytosis while their fungicidal activity for C. pseudotropicalis was statistically significantly altered and was more evident in the lepromatous than in the tuberculoid type.
  • (8) In the terminal segment of the hamster epididymidis there was some evidence of micro-merocrine protein secretion a the level of the principal cells and clear evidence of granular secretion in the light cells, presumable of glycoproteins.
  • (9) In the analysis of background fluorescence, the principal components were, as for the two-step technique, autofluorescence and propidium spectral overlap.
  • (10) However, at Period B, neutrophil numbers in the BAL fluid were increased in the principal but not in the control animals.
  • (11) Principal conclusions are: 1) rapid change to predominantly heterosexual HIV transmission can occur in North America, with serious societal impact; 2) gender-specific clinical features can lead to earlier diagnosis of HIV infection in women; 3) HIV infection in women does not pursue an inherently more rapid course than that observed in men.
  • (12) The concentrations of the principal extratesticular androgens and estradiol do not seem to have a quantitative influence on these androphilic proteins either.
  • (13) A principal function of GPIb is its attachment to von Willebrand Factor (vWF) on injured blood vessels which leads to the adhesion of platelets to these vessels.
  • (14) The principal variables influencing a particular configuration and their effects are indicated.
  • (15) The principal form of HMTs produced by these human peripheral blood monocytes has been subjected to biochemical, functional, and serological characterization.
  • (16) Micronutrient antioxidants such as alpha-tocopherol, the principal lipid-soluble antioxidant, assume potential significance because levels can be manipulated by dietary measures without resulting in side effects.
  • (17) Cytochrome oxidase histochemistry revealed patchy patterns of the enzyme activity in transverse sections through the caudal part of the ventral subnucleus of the principal sensory trigeminal nucleus, interpolar spinal trigeminal nucleus, and layer IV of the caudal spinal trigeminal nucleus in the cat.
  • (18) 3. an up-to-date review of the principal methods and systems used to measure the sedimentation rate--Automation of the Westergren initial methodology.
  • (19) • Queen Margaret Union, one of the University of Glasgow's two student unions, says 200 students there are marching on the principal's office at the moment to present an anti-cuts petition.
  • (20) This observation provides corroboration for the identification of the principal CCK-I neuron in the rat olfactory bulb as the centrally projecting middle tufted cell.

Roof


Definition:

  • (n.) The cover of any building, including the roofing (see Roofing) and all the materials and construction necessary to carry and maintain the same upon the walls or other uprights. In the case of a building with vaulted ceilings protected by an outer roof, some writers call the vault the roof, and the outer protection the roof mask. It is better, however, to consider the vault as the ceiling only, in cases where it has farther covering.
  • (n.) That which resembles, or corresponds to, the covering or the ceiling of a house; as, the roof of a cavern; the roof of the mouth.
  • (n.) The surface or bed of rock immediately overlying a bed of coal or a flat vein.
  • (v. t.) To cover with a roof.
  • (v. t.) To inclose in a house; figuratively, to shelter.

Example Sentences:

  • (1) The M&S Current Account, which has no monthly fee, is available from 15 May and is offering people the chance to bank and shop under one roof.
  • (2) The horizontal portion of the intracavernous ICA as well as the whole aspect of the aneurysm could be exposed as a result of the extended opening of the cavernous roof anterior to the posterior clinoid process.
  • (3) In 1986, Bill Heine erected a 25ft sculpture of a shark falling through the roof of his terraced house in Oxford .
  • (4) Nango's dwellings are built on skis so can be pulled around the beach, and have a glass roof to view the northern lights.
  • (5) A grassed roof, solar panels to provide hot water, a small lake to catch rainwater which is then recycled, timber cladding for insulation ... even the pitch and floodlights are "deliberately positioned below the level of the surrounding terrain in order to reduce noise and light pollution for the neighbouring population".
  • (6) For the roof, different odorants produced different activity patterns, which had profiles not simply described as regions of maximal and minimal responsiveness.
  • (7) The scheme is available to those who have one or more of the following technologies: solar PV panels (roof-mounted or stand alone), wind turbines (building mounted or free standing), hydroelectricity, anaerobic digestion (generating electricity from food waste), and micro combined heat and power (through the use of new types of boilers , for example).
  • (8) They were about to put the roof on it,” Hickman said.
  • (9) Just one problem (apart from the old roof falling off): it's 60 miles from my desk.
  • (10) On it rests the small village of Dholera – a cluster of houses with thatched roofs, muddy roads, and acres of flat, fertile land surrounding them.
  • (11) I have to put a roof over my son’s head.” Junior doctors will be balloted to decide whether to strike over a radical new contract imposed on them by the Department of Health, which redefines their normal working week to include Saturday and removes overtime rates for work between 7pm and 10pm every day except Sunday.
  • (12) Hydrogen sulfide poisoning from inhalation of roofing asphalt fumes is a rare but devastating injury.
  • (13) The keratinocytes of the blister roof showed aggregation of the tonofibrils at the periphery, and vacuolization of mitochondria and endoplasmic reticulum.
  • (14) The commemoration began when the clock on the neo-gothic Town Hall struck 12, and a maroon was fired from the roof.
  • (15) Glasgow Central station was also closed to the public after flying debris shattered part of the building's glass roof.
  • (16) Berkeley has launched a new design called the Urban House, a three-storey house with a private roof garden instead of a back garden.
  • (17) Now the fabric of the school is visibly crumbling: roofs leak and skylights are broken; the estimated cost of repairs is £1m.
  • (18) I went inside, and the sound of the rain on the roof and the darkness inside made me very afraid.
  • (19) The risk of getting malaria was greater for inhabitants of the poorest type of house construction (incomplete, mud, or cadjan (palm) walls, and cadjan thatched roofs) compared to houses with complete brick and plaster walls and tiled roofs.
  • (20) The operative method involves removal of portions of the orbital rim, orbital roof, and sphenoid bone.