A parent function is a simple representative of a family of related functions. Other members of the family are obtained from it by transformations such as translations,
reflections, stretches, and compressions of its function graph. For example, 
is commonly used as the parent for linear
functions, 
for functions represented by quadratic polynomials,
and 
for absolute-value functions.
The choice of parent is a convention for organizing related graphs rather than an intrinsic property of a function.
