is called a linear combination of $A_1, A_2, \ldots, A_r$ with coefficients $c_1, c_2, \ldots, c_r$.
#Matrix multiplication as linear combination
#Columns of a product AB as Linear Combinations
is called a linear combination of $A_1, A_2, \ldots, A_r$ with coefficients $c_1, c_2, \ldots, c_r$.
Leontieff