Q-Pochhammer
From specialfunctionswiki
The $q$-Pochhammer symbol $[a]_{n,q}$ is defined for $n=0$ by $[a]_{0,q}=1$, for $n=1,2,3,\ldots$ by the formula $$[a]_{n,q}= \displaystyle\prod_{k=0}^{n-1} [a+m]_q.$$
Properties
q-Pochhammer as sum of q-binomial coefficients
Relationship between q-factorial and q-pochhammer
Relationship between Euler phi and q-Pochhammer
Notes
Mathworld and Mathematica define the "$q$-Pochhammer symbol" to be what we call the $q$-factorial.