noun

• (by extension, Australia, New Zealand) Any alcoholic beverage.
  "I quite understood their drift, and after a stiff glass of grog, or rather more of the same, and with each a sovereign in hand, they made light of the attack, and swore they would encounter a worse madman any day for the pleasure of meeting so 'bloomin' good a bloke' as your correspondent."
• (countable, Australia, New Zealand) A glass or serving of an alcoholic beverage.
  "1950, Nevil Shute, A Town Like Alice [The Legacy], New York: William Morrow, Chapter 5, p. 138, Joe […] told them how he had been nailed up to be beaten, and they shouted another grog for him."
• (ceramics) A type of pre-fired clay that has been ground and screened to a specific particle size.

verb

• (transitive, ceramics) To grind and screen (clay) to a specific particle size.
• (intransitive, slang) To drink alcohol.
  "[…] a practice of “equal surrender.” This evocative phrase comes from Basil Sansom's ethnography […] of grogging sessions among Aboriginal communities in Darwin. Sansom argues that this style of communal drinking […]"