13-letter words containing a, p, o, r, t, i
- oppositionary — the action of opposing, resisting, or combating.
- oprahfication — the perceived increase in people’s desire to discuss their emotions or personal problems, attributed to the influence of confessional television programmes
- optical crown — an optical glass of low dispersion and relatively low refractive index. It is used in the construction of lenses
- optical drive — optical disk drive
- optical fiber — optical fibre
- optical fibre — (communications) (fibre optics, FO, US "fiber", light pipe) A plastic or glass (silicon dioxide) fibre no thicker than a human hair used to transmit information using infra-red or even visible light as the carrier (usually a laser). The light beam is an electromagnetic signal with a frequency in the range of 10^14 to 10^15 Hertz. Optical fibre is less susceptible to external noise than other transmission media, and is cheaper to make than copper wire, but it is much more difficult to connect. Optical fibres are difficult to tamper with (to monitor or inject data in the middle of a connection), making them appropriate for secure communications. The light beams do not escape from the medium because the material used provides total internal reflection. See also FDDI, Optical Carrier n, SONET.
- orchestra pit — musicians' seating in front of stage
- orchestra-pit — a group of performers on various musical instruments, including especially stringed instruments of the viol class, clarinets and flutes, cornets and trombones, drums, and cymbals, for playing music, as symphonies, operas, popular music, or other compositions.
- organotropism — Physiology. the attraction of microorganisms or chemical substances to particular organs or tissues of the body.
- ornithophobia — Fear of birds.
- orthocephalic — having a medium or intermediate relation between the height of the skull and the breadth or length.
- orthoepically — In terms of correct pronunciation.
- orthographies — Plural form of orthography.
- orthographize — to spell correctly or according to the rules of orthography.
- orthopaedical — Pertaining to orthopaedics; characteristic of orthopaedia.
- orthopinakoid — a crystalline plane
- overpotential — overvoltage.
- ovoviviparity — producing eggs that are hatched within the body, so that the young are born alive but without placental attachment, as certain reptiles or fishes.
- painted horse — paint (def 6).
- palaeocrystic — consisting of former glacial formation
- paleotropical — belonging or pertaining to a geographical division comprising the Ethiopian and Oriental regions.
- panradiometer — an instrument used for measuring radiant heat independently of wavelength
- pantisocratic — relating to pantisocracy
- paper profits — an unrealized profit due to the appreciation of something owned but not yet sold.
- paradise lost — an epic poem (1667) by John Milton.
- paranormality — the state of being paranormal
- parasitoidism — the feeding by certain insect larvae on host tissues such that the host remains alive until larval development is complete and then usually dies.
- parietal bone — either of a pair of membrane bones forming, by their union at the sagittal suture, part of the sides and top of the skull.
- parietal lobe — the middle part of each cerebral hemisphere behind the central sulcus.
- parking orbit — a temporary orbit in which a spacecraft awaits the next phase of its mission.
- parotid gland — Also called parotid gland. a salivary gland situated at the base of each ear.
- parrot's-bill — a showy, vinelike plant, Clianthus puniceus, of New Zealand, having clusters of eight white-streaked, crimson flowers.
- parthian shot — a sharp, telling remark, act, gesture, etc., made in departing.
- parti-colored — having different colors in different areas or patches; variegated: a parti-colored dress.
- participation — an act or instance of participating.
- participatory — to take or have a part or share, as with others; partake; share (usually followed by in): to participate in profits; to participate in a play.
- particleboard — a boardlike building material made by compressing sawdust or wood particles with a resin binder
- partitionable — a division into or distribution in portions or shares.
- partitionment — the act or fact of being partitioned
- passion fruit — any edible fruit of a passionflower, as the maypop.
- past anterior — a pluperfect verb (in French)
- past historic — the simple past
- pathomorphism — abnormal morphology.
- patrifocality — the system or fact of being patrifocal
- patriot's day — the third Monday in April, a legal holiday in Me. and Mass. commemorating the battles of Lexington and Concord (April 19, 1775)
- patriotically — of, like, suitable for, or characteristic of a patriot.
- patriots' day — the anniversary of the battles of Lexington and Concord (1775), celebrated the third Monday in April: a legal holiday in Massachusetts and Maine.
- patripotestal — Anthropology. of or relating to the authority exercised by a father or a father's blood relatives.
- patronization — to give (a store, restaurant, hotel, etc.) one's regular patronage; trade with.
- patronizingly — displaying or indicative of an offensively condescending manner: a patronizing greeting, accompanied by a gentle pat on the pack.