Homogeneous

A function $f(a_1,a_2,\ldots,a_n)$ is said to be homogeneous if all its terms are of the same degree in $a_i$ .

This concept of homogeneity is often used in inequalities so that one can "scale" the terms (this is possible because $f(ta_1,ta_2,\ldots,ta_n)=t^kf(a_1,a_2,\ldots,a_n)$ for some fixed $k$ ), and assume things like the sum of the involved variables is $1$ , for things like Jensen's Inequality