"The chupah will take place at 6:30 bediyuk." Bediyuk means "with a diyuk" or "exactly" and often appears on wedding invitations to ensure that the chupah will not take place more than an hour or two late.
A diyuk is an emphasis on a fine point. It comes from the Biblical word dak, referring to something thin as in the "thin, small voice" heard by Elijah (I Kings 19:12). It also means to pulverize; the recipe for the sacrificial incense requires one to "beat some of it into powder [hadek]" (Exodus 30:36).
Dak evolved from a physical description to a metaphorical sense of focusing on all the details of a concept or object. To fulfil a task according to all its requirements down to the last detail is to be medakdek.
The 11th-century Spanish Hebrew poet and philosopher, Solomon Ibn Gabirol, spoke of the "secret of the dikduk of the delightful Hebrew language." Here, dikduk refers to the system of Hebrew grammar, whose principles became a great preoccupation of Jewish scholars under Arabic influence.
Indeed, today dikduk without any adjectival prefix refers to the intricate, headache-inducing body of rules of Hebrew grammar.
Let's Schmooze: Jewish Words Today by Julian Sinclair (Continuum, £12.99)