The Collaborative International Dictionary of English v.0.48:

Carrol \Car"rol\, n. (Arch.)
   See 4th Carol.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Carol \Car"ol\, Carrol \Car"rol\, n. [OF. carole a sort of
   circular space, or carol.] (Arch.)
   A small closet or inclosure built against a window on the
   inner side, to sit in for study. The word was used as late as
   the 16th century. The term carrel, of the same has largely
   superseded its use.
   [1913 Webster +PJC]

         A bay window may thus be called a carol. --Parker.
   [1913 Webster]