Vector notation is a written method for representing quantities that possess both direction and magnitude, such as acceleration. Vectors are often represented graphically by lines with an arrow pointing in the appropriate direction.
When writing about vectors, they may be indicated by the name of the line segment with a right-facing arrow printed above the name, by applying boldface to the name of the vector, or by mathematical coordinates. Vector coordinates indicate direction, not location, so a vector written out as (-1, 3) is moving negatively one space in respect to the x axis, or left, and positively three spaces in respect to the y axis, or up. In handwriting, a squiggly line, or tilde, may be written underneath the name of the line segment to indicate that it is a vector.