IPA: /dɪˈtɜːrmɪnəsi/
KK: /dɪˈtɜːrmɪnəsi/
The state or quality of being clearly defined or determined.
The determinacy of the rules made it easy for everyone to understand the game.
Determinacy is formed from "de-" (meaning down or away) and "terminare" (meaning to limit or set boundaries). The word refers to the quality of being definite or having clear limits.
Think of 'setting boundaries' ('terminare') and 'down' ('de-') to remember that determinacy means having clear limits or being definite.