Merriam-Webster Collegiate Dictionary - dike

 I. noun  Etymology: Middle English, probably from Old Norse dik ditch and Middle Low German dik dam; akin to Old English dic ditch — more at ditch  Date: 13th century  1. an artificial watercourse ; ditch  2.  a. a bank usually of earth constructed to control or confine water ; levee  b. a barrier preventing passage especially of something undesirable  3.  a. a raised causeway  b. a tabular body of igneous rock that has been injected while molten into a fissure  II. transitive verb  (~d; diking)  Date: 14th century  1. to surround or protect with a ~  2. to drain by a ~  • ~r noun  III. variant of dyke