LCD: Liquid Crystal Display
A liquid crystal display (LCD) is an electro-optical amplitude modulator realized as a thin, flat display device made up of any number of color or monochrome pixels arrayed in front of a light source or reflector. It is often utilized in battery-powered electronic devices because it uses very small amounts of electric power.
In color LCDs each individual pixel is divided into three cells, or subpixels, which are colored red, green, and blue, respectively, by additional filters (pigment filters, dye filters and metal oxide filters). Each subpixel can be controlled independently to yield thousands or millions of possible colors for each pixel.
YLCD: Yellow LCD
Same as LCD, but with a yellow background plate.
LED: Light-emitting Diode
A light-emitting-diode (LED) (pronounced /ˌɛliːˈdiː/), is a semiconductor diode that emits light when an electric current is applied in the forward direction of the device, as in the simple LED circuit. The effect is a form of electroluminescence where incoherent and narrow-spectrum light is emitted from the p-n junction.
VFD: Vacuum fluorescent display
A vacuum fluorescent display (VFD) is a display device used commonly on consumer-electronics equipment such as video cassette recorders, car radios, and microwave ovens. Unlike liquid crystal displays, a VFD emits a very bright light with clear contrast and can easily support display elements of various colours. The technology is related to both the cathode ray tube and the nixie tube.
CRT: Cathode Ray Tube
The cathode ray tube (CRT) is a vacuum tube containing an electron gun (a source of electrons) and a fluorescent screen, with internal or external means to accelerate and deflect the electron beam, used to form images in the form of light emitted from the fluorescent screen. The image may represent electrical waveforms (oscilloscope), pictures (television, computer monitor), radar targets and others.
Because of their size and energy requirements, CRT displays where never used for hand-held devices.
PFD: Plasma Fluorescent Display
A plasma display panel (PDP) is a type of flat panel display now commonly used for large TV displays (typically above 37-inch or 940 mm). Many tiny cells located between two panels of glass hold an inert mixture of noble gases. The gas in the cells is electrically turned into a plasma which then excites phosphors to emit light. Plasma displays are commonly confused with LCDs, another lightweight flatscreen display but with very different technology.
Quotes taken from Wikipedia