\begin{definition}[Definition:Fibonomial Coefficient]
Let $n \in \Z_{\ge 0}$ and $k \in \Z$.
Then the '''Fibonomial coefficient''' $\dbinom n k$ is defined as:
:$\dbinom n k_\FF = \begin{cases} 0 & : n < 0, n > k \\
1 & : n \ge 0, k = 0 \\
\dfrac {F_n F_{n - 1} \cdots F_{n - k + 1} } {F_k F_{k - 1} \cdots F_1} = \ds \prod_{j \mathop = 1}^k \dfrac {F_{n - k + j} } {F_j} & : \text{otherwise}
\end{cases}$
where $F_n$ denotes the $n$th Fibonacci number.
\end{definition}