Tumor, tumescent, and tumulus — but not tumult — all come from or are related to the Latin tumere, "to swell," though you won't have a swell time with any of these things. Tomb, too, is etymologically related and takes us closer to the meaning we seek.
A tumulus is an artificial mound, especial one over the grave of a body. Barrow is a more common synonym for tumulus, though with what we know about hygiene and the possible effects of flood, neither is common anymore.
A graveyard full of such mounds, growing like tumors under the grass, is either tumulose or tumulous, take your pick.
Tumultuous, that word that is almost but not quite tumulus, comes from the Latin tumultus, "akin to Sanskrit tumula noisy," says Merriam-Webster's.
|Yes, that looks like a doorway, but nothing good can come from stepping through it.|
The aged sisters draw us into life: we wail, batten, sport, clip, clasp, sunder, dwindle, die: over us dead they bend. First, saved from waters of old Nile, among bulrushes, a bed of fasciated wattles: at last the cavity of a mountain, an occulted sepulchre amid the conclamation of the hillcat and the ossifrage. And as no man knows the ubicity of his tumulus nor to what processes we shall thereby be ushered nor whether to Tophet or to Edenville in the like way is all hidden when we would backward see from what region of remoteness the whatness of our whoness hath fetched his whenceness.More revealing is an excerpt from W. Howship Dickinson's King Arthur in Cornwall, an attempt in 1900 to set down the true history of King Arthur:
Glastonbury was one of the earliest seats of Christianity in this island, and no doubt was reverenced as such in the time of Arthur. The tumulus and the churchyard were at this time competing as receptacles for the dead — the tumulus as a heathen, the churchyard as a Christian place of rest.A tumulus and a tumult do have one thing in common: They're better seen from the outside.