variable-density recording system
51electronics — /i lek tron iks, ee lek /, n. (used with a sing. v.) the science dealing with the development and application of devices and systems involving the flow of electrons in a vacuum, in gaseous media, and in semiconductors. [1905 10; see ELECTRONIC,… …
52optics — /op tiks/, n. (used with a sing. v.) the branch of physical science that deals with the properties and phenomena of both visible and invisible light and with vision. [1605 15; < ML optica < Gk optiká, n. use of neut. pl. of OPTIKÓS; see OPTIC,… …
53List of computing and IT abbreviations — This is a list of computing and IT acronyms and abbreviations. Contents: 0–9 A B C D E F G H I J K L M N O P Q R S T U V W X Y …
54earthquake — /errth kwayk /, n. 1. a series of vibrations induced in the earth s crust by the abrupt rupture and rebound of rocks in which elastic strain has been slowly accumulating. 2. something that is severely disruptive; upheaval. [1300 50; ME erthequake …
55eye, human — ▪ anatomy Introduction specialized sense organ capable of receiving visual images, which are then carried to the brain. Anatomy of the visual apparatus Structures auxiliary to the eye The orbit The eye is protected from mechanical injury… …
56Magnetic stripe card — An example of the reverse side of a typical credit card: Green circle #1 labels the Magnetic stripe A magnetic stripe card is a type of card capable of storing data by modifying the magnetism of tiny iron based magnetic particles on a band of… …
57nebula — nebular, adj. /neb yeuh leuh/, n., pl. nebulae / lee , luy /, nebulas. 1. Astron. a. Also called diffuse nebula. a cloud of interstellar gas and dust. Cf. dark nebula, emission nebula, reflection nebula …
58Plate tectonics — The tectonic plates of the world were mapped in the second half of the 20th century …
59Egypt, ancient — Introduction civilization in northeastern Africa dating from the 3rd millennium BC. Its many achievements, preserved in its art and monuments, hold a fascination that continues to grow as archaeological finds expose its secrets. This article… …
60Magnetar — For the hedge fund, see Magnetar Capital. Artist s conception of a magnetar, with magnetic field lines A magnetar is a type of neutron star with an extremely powerful magnetic field, the decay of which powers the emission of copious amounts of… …
