raster
UK[ˈræstə]US[ˈræstər]
n
A pattern of parallel scanning lines followed by the electron beam on a television screen or computer monitor.
n
A rectangular pattern of parallel scanning lines that guides the electron beam on a cathode-ray tube or is used to represent and store an image in a computer.
Morpheme Breakdown
rast
er
rast
scrape, rake
er
agent/instrument suffix
Etymology
The word 'raster' entered English from German in the mid-20th century, specifically from the field of television technology. The German verb 'rasten' (to scrape, to rake) metaphorically described the action of the electron beam scanning across the screen in a systematic, line-by-line pattern, much like a rake scraping across soil. The '-er' suffix forms a noun denoting the instrument or pattern that performs this action. Thus, the term's logic moves from the concrete action of scraping in parallel lines to the abstract technical pattern used in image rendering and display.
Analysis
Structure: rast (scrape, rake) + er (agent/instrument suffix)
The morpheme 'rast' originates from the German verb 'rasten', meaning "to scrape" or "to rake". The suffix 'er' is an English agentive suffix, often indicating an instrument or device that performs an action.
Examples
The image on older CRT monitors was created by a moving electron beam following a fixed raster.
The graphic was converted from a vector format into a raster format composed of individual pixels.
A common problem in early video games was visible raster lines during screen refresh.