"small stalk-like structure from an organ in an animal body," 1620s, from French pedicule or directly from Latin pediculus "footstalk, little foot," diminutive of pedem (nominative pes) "foot," from PIE root *ped- "foot."
1560s, "base supporting a column, statue, etc.; that which serves as a foot or support," from French piédestal (1540s), from Italian piedistallo "base of a pillar," from pie "foot" (from Latin pes "foot;" from PIE root *ped- "foot") + di "of" + Old Italian stallo "stall, place, seat," from a Germanic source (see stall (n.1)). The spelling in English was influenced by Latin pedem "foot." An Old English word for it was fotstan, literally "foot-stone." Figurative sense of put (someone) on a pedestal "regard as highly admirable" is attested by 1859.
"footstalk of a leaf, the support by which the blade of a leaf is attached to the stem," 1753, from French pétiole (18c.), from Late Latin petiolus, a misspelling of peciolus "stalk, stem," literally "little foot," diminutive of pediculus "foot stalk," itself a diminutive of pes (genitive pedis) "foot," from PIE root *ped- "foot." Given its modern sense by Linnaeus. Related: Petiolar; petiolate.
c. 1400, "a deep pool," from plunge (v.). From late 15c. as "a sudden pitch forward;" meaning "act of plunging, a sudden immersion in something" is from 1711. Figurative use in take the plunge "commit oneself" is by 1823, from an earlier noun sense of "point of being in trouble or danger, immersion in difficulty or distress" (1530s); the exact phrase might owe its popularity to its appearance in "The Vicar of Wakefield" (1766), which everybody read:
Mr. Thornhill's assurance had entirely forsaken him : he now saw the gulph of infamy and want before him, and trembled to take the plunge. He therefore fell on his knees before his uncle, and in a voice of piercing misery implored compassion.