sarsen a silicified sandstone boulder of a kind which occurs on the chalk downs of southern England. Such stones were used in constructing Stonehenge and other prehistoric monuments. They consist of a form of quartzite, and were probably formed as a duricrust in the Pliocene period. The word is recorded from the late 17th century, and is apparently a variant of Saracen.

sarsen large boulder. XVII. Earlier in Saracen's and Sarsdon stones, Sarsdens, and supposed to be identical with SARACEN.