[1] : The Collaborative International Dictionary of English v.0.48

sill \sill\ si^l, n. oe. sille, sylle, as. syl, syll; akin
   to g. schwelle, ohg. swelli, icel. syll, svill, sw. syll,
   dan. syld, goth. gasuljan to lay a foundation, to found.
   the basis or foundation of a thing; especially, a horizontal
   piece, as a timber, which forms the lower member of a frame,
   or supports a structure; as, the sills of a house, of a
   bridge, of a loom, and the like. hence:
   a the timber or stone at the foot of a door; the threshold.
   b the timber or stone on which a window frame stands; or,
       the lowest piece in a window frame.
   c the floor of a gallery or passage in a mine.
   d a piece of timber across the bottom of a canal lock for
       the gates to shut against.
       1913 webster

   sill course arch., a horizontal course of stone, terra
      cotta, or the like, built into a wall at the level of one
      or more window sills, these sills often forming part of
      it.
      1913 webster
see also:
sill course 

Course >> C Words
Course, definition of term: Course
course_pag1.html

Sill >> S Words
Sill, definition of term: Sill
sill_pag1.html

Of Course >> O Words
Of Course, definition of term: Of Course
of+course_pag1.html

Golf Course >> G Words
Golf Course, definition of term: Golf Course
golf+course_pag1.html

In The Course O >> I Words
In The Course O, definition of term: In The Course O
in+the+course+o_pag1.html