Tree forest
Quatrain
The common term is Tree Line. There is probably some fancy scientific name for it too.
Tree line.
The official definition for the term assembly line is "a series of workers and machines in a factory by which a succession of identical items is progressively assembled."
define the term "electromegnetism".
A single line is not sufficient to define a plane. You can find a plane such that the line is in it. But if you then rotate the plane using that line as the axis of rotation, you can get an infinite number of planes such that the line belongs to each and every one of the planes.
Define the Great Line was created in 2006-01.
define a subset
a coniferous tree
baseline on which figures appear to stand in artwork, usually term pertains to relief sculptures
define the term sound
This depends on how you define "usless"