From WordNet (r) 3.0 (2006) [wn]:
causeway
n 1: a road that is raised above water or marshland or sand
v 1: provide with a causeway; "A causewayed swamp"
2: pave a road with cobblestones or pebbles
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Causeway \Cause"way\ (k[add]z"w[asl]), Causey \Cau"sey\
((k[add]"z[y^]), n. [OE. cauci, cauchie, OF. cauchie, F.
chauss['e]e, from LL. (via) calciata, fr calciare to make a
road, either fr. L. calx lime, hence, to pave with limestone
(cf. E. chalk), or from L. calceus shoe, from calx heel,
hence, to shoe, pave, or wear by treading.]
A way or road raised above the natural level of the ground,
serving as a dry passage over wet or marshy ground.
[1913 Webster]
But that broad causeway will direct your way. --Dryden.
[1913 Webster]
The other way Satan went down
The causey to Hell-gate. --Milton.
[1913 Webster] Causewayed