Weyren Stride (or WS) is a unit of measure used on Eamon to express distances at sea. The unit is used in the adventure Buccaneer! by Pat Hurst in which the coordinates of islands in the Malphigian Sea are given in Weyren Strides south and west of the harbor at Evenhold.
The unit is named for Weyren, god of water and the seas, who is sometimes symbolized as a sea giant. Hurst doesn't define the length of Weyren's stride, but given that the islands in Buccaneer! are seemingly not far from Evenhold it may be similar to a league.