Economic Definition of curve. Defined.
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Term curve Definition: A line with a non-constant, or changing, slope. In technical circles, the word "line" is often used if the slope is constant and the word "curve" is used to mean the slope is not constant. However, economics often uses the terms line and curve interchangeably, as in "demand line" or "demand curve." Unless your course is taught be an economist with a really strong mathematical inclination, you too can safely use both terms interchangeably.