IPA: /dɪˈskrɛʃənəri/
KK: /dɪˈskrɛʃənɛri/
Relating to something that can be used or decided upon according to one's own judgment or choice.
The company has a discretionary budget that managers can allocate as they see fit.
Discretionary is formed from "discretion" (from Latin "discretio", meaning separation or distinction) and the suffix "-ary" (meaning pertaining to or connected with). The word describes something that is related to the ability to make choices or decisions based on one's judgment.
Think of 'discretion' as the ability to make choices or distinctions, and remember that 'discretionary' means related to making those choices.