\begin{definition}[Definition:Field of Rational Numbers]
The '''field of rational numbers''' $\struct {\Q, + \times, \le}$ is the set of rational numbers under the two operations of addition and multiplication, with an ordering $\le$ compatible with the ring structure of $\Q$.
When the ordering $\le$ is subordinate or irrelevant in the context in which it is used, $\struct {\Q, +, \times}$ is usually seen.
\end{definition}