All articles starting with P

Ptah

Ptah (Egyptian Ptḥ), mummiform creator god and patron of craftsmen at Memphis, identified by Greeks with Hephaestus; his temple Hwt-ka-Ptah gave Egypt its Greek name, and the Shabaka Stone records his creation by heart and tongue.

Ptahemwia

Ptahemwia was a high-ranking Egyptian official of the Nineteenth Dynasty under Ramesses II, serving as royal scribe and Overseer of the Treasury of the Ramesseum.

Ptahhotep (vizier of Djedkare)

Ptahhotep, also known as Ptahhotep I or Ptahhotpe, was a vizier of ancient Egypt who served King Djedkare Isesi in the late Fifth Dynasty, around 2400 BC.

Ptahhotep Tjefi

Ptahhotep Tjefi, also known as Ptahhotep Djefi, was a vizier of ancient Egypt who served King Djedkare Isesi at the end of the Fifth Dynasty, around the 25th century BCE.

Ptahmose (vizier)

Ptahmose was an Egyptian official of the late 18th Dynasty who served Amenhotep III as high priest of Amun, vizier, and head of building projects.

Ptahmose I (High Priest of Ptah)

Ptahmose I was High Priest of Ptah at Memphis under Pharaoh Thutmose III of the 18th Dynasty, when the Ptah priesthood was among Egypt's most powerful offices.

Ptahmose, son of Menkheper

Ptahmose, son of Menkheper, was an 18th-Dynasty Egyptian official who served as High Priest of Ptah at Memphis, bearing the title "Greatest of the Directors of craftsmen" and known from the office's published succession lists.

Ptahshepses (vizier)

Ptahshepses was a vizier of ancient Egypt's Fifth Dynasty who served King Nyuserre, married Princess Khamerernebty, and built at Abusir the largest private mastaba tomb known from the Old Kingdom.

PTAM

PTAM (Parallel Tracking and Mapping) is an augmented reality camera tracking system that builds 3D point-feature maps in parallel with tracking, presented at ISMAR 2007.

PTAS

A PTAS, or polynomial-time approximation scheme, is a family of algorithms for NP-hard optimization problems that returns solutions within any chosen accuracy, for fixed accuracy running in polynomial time.

PTBP1

PTBP1 (PTB, hnRNP I) is a ubiquitous human RNA-binding protein on chromosome 19p13.3 with four quasi-RRM domains that binds polypyrimidine tracts, regulating alternative splicing, neural development, metabolism, and cancer, and is central to the disputed glia-to-neuron conversion field.

PTC Inc.

PTC Inc., formerly Parametric Technology Corporation, is an American industrial software company headquartered in Boston. Founded in 1985, it is known for the Creo CAD suite and Windchill PLM platform.

PTCH1

PTCH1 (patched 1), also known as PTC1 or BCNS, is a tumor suppressor gene on chromosome 9q22.32 encoding the Hedgehog receptor patched-1; its loss-of-function mutations cause Gorlin syndrome and occur in basal cell carcinoma and medulloblastoma.

PTCL Group

PTCL Group is the business group of Pakistan Telecommunication Company Limited, Pakistan's largest integrated telecom operator, majority owned by the government and controlling fixed broadband and Ufone mobile services.

PTEN (gene)

PTEN (phosphatase and tensin homolog, MMAC1) is a tumor suppressor gene on chromosome 10q23 encoding a PIP3 phosphatase that antagonizes PI3K–AKT–mTOR signaling; lost in many cancers and mutated in Cowden syndrome and PTEN hamartoma tumor syndrome.

Oct 20, 2026

PTEN hamartoma of soft tissue

PTEN hamartoma of soft tissue (PHOST), also called PTEN-related hamartoma, is a rare benign intramuscular overgrowth of fat, fibrous tissue, and abnormal vessels in PTEN hamartoma tumor syndrome, often mistaken for arteriovenous malformation.

PTEN hamartoma tumor syndrome

PTEN hamartoma tumor syndrome (PHTS), also called Cowden syndrome spectrum, is an autosomal dominant PTEN-gene disorder causing hamartomas, macrocephaly, autism risk, and high lifetime breast, thyroid, endometrial, renal, and colorectal cancer risk.

Pteranodon

Pteranodon, a toothless Late Cretaceous pterosaur from the Western Interior Seaway, Kansas state flying fossil since 2014; wingspan about 7 m, fish-eating, sexually dimorphic, named by Marsh in 1876.

Pteraspis

Pteraspis, extinct Early Devonian jawless fish genus of armored heterostracans (Pteraspididae, named by Kner 1847), lived 419-409 Ma in shallow marine waters of Europe and North America; bottom-feeder with bony head plates.

Pteria (bivalve)

Pteria (winged oysters) is a genus of byssate marine bivalves in the family Pteriidae, type species Pteria hirundo, Triassic origin, wing-shaped shells with a large posterior auricle, and Pteria penguin cultured for mabe pearls.

Pteria (city)

Pteria (Ancient Greek Πτερία), also called Pterium, was a city of Cappadocia east of the Halys river in central Anatolia, captured and enslaved by Croesus of Lydia.

Pteria penguin

Pteria penguin (Röding, 1798), the winged pearl oyster or blackwing pearl-oyster (マベ), is an Indo-West Pacific pteriid bivalve attached by a single fused byssus and widely cultured for mabé half-pearls, notably in Tonga.

Pteridaceae

Pteridaceae, the maidenhair fern family (syn. Adiantaceae, Vittariaceae, Parkeriaceae), is a monophyletic fern family of over 1000 species in five subfamilies (PPG I 2016), defined by pseudoindusia, trilete spores, and x = 29 or 30 chromosomes.

Pteridine

Pteridine is an aromatic heterocyclic organic compound with the molecular formula C₆H₄N₄, consisting of a pyrimidine ring fused to a pyrazine ring, parent to pterins and the cofactors tetrahydrofolate and tetrahydrobiopterin.

Oct 20, 2026

Pteridium

Pteridium (bracken, bracken fern), genus of Dennstaedtiaceae ferns; cosmopolitan, 20 accepted species, two diploid species P. aquilinum and P. esculentum; toxic, ptaquiloside carcinogen, IARC Group 2B, invasive weed.

Pteridium aquilinum

Pteridium aquilinum (bracken fern), Dennstaedtiaceae, is a rhizomatous fern native from Macaronesia and Africa to Siberia and Iran. It contains the carcinogen ptaquiloside, poisons livestock, and contaminates milk and water.

Pteridomania

Pteridomania, or fern fever, was the Victorian passion for collecting and growing ferns that swept Britain between 1837 and 1914, coined by Charles Kingsley in 1855.

Pteridophyte

Pteridophyte, informal term for free-sporing vascular plants, comprising lycophytes and ferns; spore reproduction, independent gametophyte and sporophyte; PPG I 2016 recognizes 11,916 species, 337 genera, 51 families, 14 orders, two classes.

Pteriidae

Pteriidae, the pearl oyster family (Pinctada, Pteria), marine bivalves of the superfamily Pterioidea; Triassic origin about 230 Ma, byssally attached tropical shelf shells, main source of cultured pearls and mother-of-pearl.