[pen-tad] /ˈpɛn tæd/
a period of five years.
a group of five.
the number five.
Chemistry. a pentavalent element or group.
Climatology. a period of five consecutive days.
a group or series of five
the number or sum of five
a period of five years
(chem) a pentavalent element, atom, or radical
(meteorol) a period of five days
1650s, from Greek pentas (genitive pentados) “group of five” (see five). Meaning “period of five years” is from 1880; meaning “period of five days” is from 1906, originally in meteorology.
[pen-tuh-dak-tl, -til] /ˌpɛn təˈdæk tl, -tɪl/ adjective 1. having five digits on each hand or foot. 2. having five fingerlike projections or parts. /ˌpɛntəˈdæktɪl/ adjective 1. (of the limbs of amphibians, reptiles, birds, and mammals) consisting of an upper arm or thigh, a forearm or shank, and a hand or foot bearing five digits
[pen-tuh-dek-uh-gon, -guh n] /ˌpɛn təˈdɛk əˌgɒn, -gən/ noun, Geometry. 1. a polygon having 15 angles and 15 sides.
[pen-tuh-i-rith-ri-tawl, -tol] /ˌpɛn tə ɪˈrɪθ rɪˌtɔl, -ˌtɒl/ noun, Chemistry. 1. a white, crystalline, water-soluble powder, C 5 H 1 2 O 4 , used chiefly in the manufacture of alkyd resins, varnishes, plasticizers, and explosives.
noun, Chemistry, Pharmacology. 1. a white, crystalline, water-insoluble, explosive solid, C 5 H 8 N 4 O 1 2 , used chiefly as a high explosive and as a vasodilator in treating angina pectoris.