In our sonnet-session last night we talked about The Windhover by Gerard Manley Hopkins and the word sillion came up.
No wonder of it: shéer plód makes plough down sillion
Shine, and blue-bleak embers, ah my dear,
Fall, gall themselves, and gash gold-vermilion.
– from The Windhover, by Gerard Manley Hopkins
Our teacher told us it meant the shine of new plowed fields and when I remembered to google it (it not being found in my iphone oxford):
Sillion: Coined by Gerard Manley Hopkins in his 1877 (published posthumously in 1918) poem The Windhover?; perhaps from French sillon (“furrow”).