Plain English Meaning
After looking at the situation and the options, you pick the one you're going to actually do.
Full Definition
In the DECIDE decision-making model, the step in which the pilot deliberately selects one course of action from the alternatives available, based on the information gathered and the consequences considered for each option.
Context Anchor
Seen in aeronautical decision-making when a pilot has recognized a problem or change and must decide what action to take next.
Derivation
From Old English 'ceosan,' meaning 'to select or pick.' In ADM the word is used in its everyday sense, but it is elevated to a formal step — the moment a pilot commits to one option rather than drifting between possibilities.