oculists' stamp
[Ar].
Small rectangular tables of stone, Roman in date, with inscriptions neatly cut in retrograde on the sides for marking cakes of eye ointment with the author of its prescription.
oculus
[Co].
1
A decorative motif used on pottery and in rock art comprising a pair of circles or spirals resembling a pair of eyes. Such designs are widely found in western Europe in the 3rd millennium
bc
, especially in Spanish Copper Age ceramics, and in
PASSAGE GRAVE ART
.
2
A round window or opening in the top of a dome.
OD
[Ab].
odeum
[MC].
A small building in form and plan like a theatre with semi-circular seating. Some were roofed. Chiefly used for musical contests, concerts, and meetings.
Odoacer
[Na].
Skirian officer elected Roman emperor in ad 476 in opposition to Romulus and his father Orestes. He ruled Italy until defeated and killed by Theodoric the Great in ad 493.
Offa's Dyke, England
[Si].
A very substantial linear earthwork believed to have been built by King
OFFA
of Mercia in the 8th century
ad
as a frontier between his kingdom and the lands to the west. The earthwork comprises a large bank to the east and a ditch to the west. It runs for more than 192km from Treuddy in the north to Chepstow in the south, close to the modern border of England and Wales. Studies by Sir Cyril Fox and others, however, show that it is not a single earthwork but rather a series of constructions joined together and in some places running roughly parallel to each other.
[Rep.: C. Fox , 1955,
Offa's Dyke
. London: British Academy]