a line drawn on a map connecting points of equal height
"The hiker studied the topographic map to follow the contour lines that represented his current elevation."
any spatial attributes (especially as defined by outline)
"he could barely make out their shapes"
a feature (or the order or arrangement of features) of anything having a complex structure
"the contours of the melody"
"it defines a major contour of this administration"
An outline, boundary or border, usually of curved shape.
"The artist carefully traced the soft contour of her friend's profile on the canvas."
In plain English: A contour is the outline of something that shows its shape and how it curves across a surface.
"The artist traced the contour of her hand with charcoal to create a detailed sketch."
Usage: Use the noun contour to describe any line that follows the natural curve and surface features of an object's edge. When referring specifically to landforms in geography, it denotes the three-dimensional shape created by elevation changes rather than a simple flat outline.
form the contours of
"As she sat up, her face began to take on the sharp contours of a sculptor's work in progress."
To form a more or less curved boundary or border upon.
"The dark clouds began to contour around the silhouette of the distant mountain range."
In plain English: To contour means to shape something by following its natural lines and curves.
"The artist carefully contoured each muscle to make the sculpture look more realistic."
The word entered English from French, where it originally meant the act of going around or encircling something. Its meaning has remained consistent with its original sense of outlining a shape by following its curves.