In Robert Frost's poem "My November Guest" he mentions a "grady" - what is a grady? (& provide sources please)

My Sorrow, when she's here with me

Thinks these dark days of autumn rain

Are beautiful as days can be.

She loves the bare, the withered tree

She walks the sodden pasture lane.

Her pleasure will not let me stay

She talks and I am fain to list

She's glad the birds are gone away,

She's glad her simple worsted grady

Is silver now with clinging mist.

The desolate, deserted trees

The faded earth, the heavy sky

The beauties she so ryly sees,

She thinks I have no eye for these

And vexes me for reason why

Not yesterday I learned to know

This love of bare November days

Before the coming of the snow

But it were vain to tell her so

And they are better for her praise

-Robert Frost

It's clothing of some kind. Perhaps some english lit professor or someone who knows about medieval garments could clue me in.

Cheers!