
1) Loophole, old style 2) Old eyelet
Found on
https://www.crosswordclues.com/clue/oillet

• (n.) A small opening or loophole, sometimes circular, used in mediaeval fortifications. • (n.) A small circular opening, and ring of moldings surrounding it, used in window tracery in Gothic architecture.
Found on
http://thinkexist.com/dictionary/meaning/oillet/

an eye hole. Roundel at the end of a cross shaped arrow loop
Found on
http://www.castles-of-britain.com/glossary.htm
Oil'let noun [ See
Eyelet .]
(Architecture) (a) A small opening or loophole, sometimes circular, used in mediæval fortifications.
(b) A small circular opening, and ring of moldings surrounding it, used in window tracery in Gothic architecture. [ Written also
oylet ...
Found on
http://www.encyclo.co.uk/webster/O/15

In architecture an oillet is a small opening or loop-hole, sometimes circular, used in mediaeval fortifications from which defenders would shoot arrows at besiegers (see also arbalestena). The term is also used to describe a small circular opening, and ring of mouldings surrounding it, used in window tracery in Gothic architecture.
Found on
http://www.probertencyclopaedia.com/browse/TO.HTM
No exact match found.