The term "Mug Up" was used in coastal communities by the mid-1800s to describe any snack or coffee break throughout the day or evening.

“Mug ups" were an important part of life for fishermen. They would gather and have a hearty meal and warm up whenever they could take a break. Today, this nautical expression still describes a gathering of people for a drink and meal

Today, Mug-up is used by Scouts Canada to describe an evening snack (after dinner, but before Campfire). It is usually soup or hot chocolate and something to munch on (grilled cheese, etc).
We'll meet for a mug-up with the boys when we reach harbour.
by That Graham Guy September 26, 2011
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When 2 people are kissing in a corner, typically a shady club or house party.
Did you see Jenn mugging up with Rob last night?
by Cresse August 26, 2005
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Usually morning coffee break. Still used on the waterfront in New England fishing towns particularly Gloucester, MA. Term was used in the movie Captains Corageous ( 1925, Spenser Tracy ) to add local flavor to this movie about the hard life of the Gloucester fishermen.
by FFbob August 31, 2012
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We'll be driving straight through, so now's your last chance to mug up.
by mandingoh May 5, 2005
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