sill

noun \ ˈsil \
Updated on: 24 Nov 2017

Definition of sill

1 : a horizontal piece (such as a timber) that forms the lowest member or one of the lowest members of a framework or supporting structure: such as
a : the horizontal member at the base of a window
b : the threshold of a door
2 : a tabular body of igneous rock injected while molten between sedimentary or volcanic beds or along foliation planes of metamorphic rocks
3 : a submerged ridge at relatively shallow depth separating the basins of two bodies of water

Recent Examples of sill from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'sill.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of sill

Middle English sille, from Old English syll; akin to Old High German swelli beam, threshold

Other Building Terms


SILL Defined for English Language Learners

sill

noun

Definition of sill for English Language Learners

  • : the shelf at the bottom of a window frame

  • : a piece of wood, metal, or stone at the bottom of a doorframe

  • : the part of the frame of a car that is directly under its doors


SILL Defined for Kids

sill

noun \ ˈsil \

Definition of sill for Students

1 : a heavy horizontal piece (as of wood) that forms the bottom part of a window frame or a doorway
2 : a horizontal supporting piece at the base of a structure


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