Effective nuts is the strongest possible hand given current board and opponents’ likely ranges.
Explanation. The “nuts” means the unbeatable hand, but “effective nuts” adjusts for board context or opponents’ holdings. For example, on a four‑flush board you might hold the highest flush, which is the “effective nuts” if no higher one exists in play. It guides decision-making: if you hold the effective nuts, you can play confidently for value.