Someone recently mentioned the "plain meaning" rule in one of my questions about statutory interpretation. Is there an official dictionary - like Merriam-Webster - that judges are supposed to rely on? Or do we assume that any of the leading publishers of dictionaries have essentially identical definitions?
I don't believe there is a single "standard" dictionary that judges use. Presumably any well regarded and common one will do as long as it can be cited. You can see from Justice Alito's opinion in Intel Investment Policy Comm vs Sulyma that he references several dictionaries.
Although ERISA does not define the phrase “actual knowledge,” its meaning is plain. Dictionaries are hardly necessary to confirm the point, but they do. When Congress passed ERISA, the word “actual” meant what it means to-day: “existing in fact or reality.” Webster’s Seventh New Collegiate Dictionary 10 (1967); accord, Merriam-Webster’s Collegiate Dictionary 13 (11th ed. 2005) (same); see also American Heritage Dictionary 14 (1973) (“In existence;real; factual”); id., at 18 (5th ed. 2011) (“Existing in reality and not potential, possible, simulated, or false”). So did the word “knowledge,” which meant and still means “the fact or condition of being aware of something.” Webster’s Seventh New Collegiate Dictionary 469 (1967); accord, Merriam-Webster’s Collegiate Dictionary 691 (2005) (same); see also American Heritage Dictionary 725 (1973) (“Familiarity, awareness, or understanding gained through experience or study”); id., at 973 (2011) (same).
Thus, to have “actual knowledge” of a piece of information, one must in fact be aware of it. Legal dictionaries give “actual knowledge” the same meaning: “[r]eal knowledge as distinguished from presumed knowledge or knowledge imputed to one.” Ballentine’s Law Dictionary 24 (3d ed. 1969); accord, Black’s Law Dictionary 1043 (11th ed. 2019) (defining “actual knowledge” as “[d]irect and clear knowledge, as distinguished from constructive knowledge”).