(n.) the shadows or dappled light cast by trees
One of 2017’s most popular Haggard Hawks tweets spiked back up in our mentions the other day, and it reminded us that we never actually got round to explaining it in a little more detail: mogshade is the shade cast by a canopy of trees.
The mog here is thought to be a corruption of mock, which as well as implying that the dappled shadows cast by trees don’t constitute the most comprehensive cover from the sun is also an old dialect word for a tree stump. Alternatively, if neither of those interpretations is correct, then it has been suggested that mog might in some way be related to the word muggy—the kind of hot and sultry weather that might have you running for shade below a tree, or the kind of stuffy, stifling air you mind find in dense forest.
As words go, mogshade is a fairly old one, first recorded in a glossary of appropriately rustic terms included in Systema Agriculturæ, a 1669 guide to all things rural—or, as its subtitle put it, “the mystery of husbandry ... published for the common good.”