A plane formed by the intersection of a horizontal number line called the x-axis and a vertical number line called the y-axis.

A mathematical statement in two variables using the inequality symbols <, >, ≤, or ≥ to show the relationship between two expressions. When the inequality symbol is replaced by an equal sign, the resulting related equation will graph as a straight line.

The point where the x-axis and the y-axis intersect on the coordinate plane (0, 0).

Two lines that lie in the same plane and intersect at a 90º angle.

The x- and y-axes divide the coordinate plane into four regions. These regions are called quadrants.

The ratio of the vertical change to the horizontal change of two points on a line.

A linear equation written in the form y = mx + b, where m represents the slope of the line, and b represents the y-value of the y-intercept, (0, b).

The point where the graph of a linear equation intersects the x-axis (x, 0).

The point where the graph of a linear equation intersects the y-axis (0, y).

axis	One of two perpendicular lines of a coordinate place that intersect at the origin. The plural form of axis is axes.
boundary line	A line that divides the coordinate plane into two regions. If points along the boundary line are included in the solution set, then a solid line is used; if points along the boundary line are not included then a dotted line is used.
coordinate plane	A plane formed by the intersection of a horizontal number line called the x-axis and a vertical number line called the y-axis.
linear equation	An equation in two variables whose ordered pairs graph as a straight line.
linear inequality	A mathematical statement in two variables using the inequality symbols <, >, ≤, or ≥ to show the relationship between two expressions. When the inequality symbol is replaced by an equal sign, the resulting related equation will graph as a straight line.
linear relationship	A linear relationship exists between two variables if, when you plot their values on a coordinate system, you get a straight line.
ordered pair	A pair of numbers that indicates a point on a coordinate plane.
origin	The point where the x-axis and the y-axis intersect on the coordinate plane (0, 0).
parallel lines	Two or more lines that lie in the same plane but which never intersect.
perpendicular lines	Two lines that lie in the same plane and intersect at a 90º angle.
quadrant	The x- and y-axes divide the coordinate plane into four regions. These regions are called quadrants.
rise	The vertical change between two points on a line.
run	The horizontal change between two points on a line.
slope	The ratio of the vertical change to the horizontal change of two points on a line.
slope-intercept form	A linear equation written in the form y = mx + b, where m represents the slope of the line, and b represents the y-value of the y-intercept, (0, b).
x-axis	The horizontal axis of a coordinate plane. Also the horizontal axis of a bar graph or histogram.
x-coordinate	The first number in an ordered pair, which tells the distance to the right or left from the origin when graphing in a coordinate plane.
x-intercept	The point where the graph of a linear equation intersects the x-axis (x, 0).
y-axis	The vertical axis of a coordinate plane. Also the vertical axis of a bar graph or histogram.
y-coordinate	The second number in an ordered pair, which tells the distance to move up or down from the origin when graphing in a coordinate plane.
y-intercept	The point where the graph of a linear equation intersects the y-axis (0, y).