The phrase "a sill" is correct and usable in written English.
It can be used to refer to a horizontal ledge or surface, typically at the bottom of a window or door frame.
Example: "She placed the flower pot on a sill to let it get enough sunlight."
Alternatives: "a ledge" or "a window ledge".
But still — a ceiling fan, a sill, & a souse who hung On my every world.
Now, the tide has to work its way up to a sill, then flood in.
The jambs were spanned by a lintel with abstract patterns, while a carved head stood between them as a sill.
It is on a window sill on the Via Garibaldi, not on a sill of the United States pavilion.
His poetry includes Mixed Feelings (1951), A Word Carved on a Sill (1956), Weep Before God (1961), Wildtrack (1965), Letters to Five Artists (1969), and Feng (1975).
After a scramble up a rubble-strewn incline, we rested in a large watchtower, each sitting on a sill of one of the several windows.
So far we've got: the floor, a table and/or desk, a chair, a window sill, a dresser, and your bed.
The analysis of the crustal deformation data that was a precursor of the eruption showed that there is a sill-like pressure source at a shallow depth.
As an example, we try adding a sill-like deformation source beneath Mt. Aso, proposed by a receiver function study (Abe et al. 2010), to the base model.
The crustal deformation before and after one of these eruptions revealed that a sill-like deformation source in the shallow part of Motoyama rapidly inflated before and deflated after the beginning of the eruption.
The most suitable model to explain the subsidence (2009 2014) was a sill-like tensile crack estimated to be −4.7 m in opening, 1.5 km in width, 2.5 km in depth, and dipping at −15°.
