SILL

Sill

In geology, a sill is a tabular sheet intrusion that has intruded between older layers of sedimentary rock, beds of volcanic lava or tuff, or even along the direction of foliation in metamorphic rock. The term sill is synonymous with concordant intrusive sheet. This means that the sill does not cut across preexisting rocks, in contrast to dikes, discordant intrusive sheets which do cut across older rocks. Sills are fed by dikes, except in unusual locations where they form in nearly vertical beds attached directly to a magma source. The rocks must be brittle and fracture to create the planes along which the magma intrudes the parent rock bodies, ...

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sill

Noun

  1. (also window sill) A horizontal slat which forms the base of a window.
    She looked out the window resting her elbows on the window sill.
  2. A horizontal, structural member of a building near ground level on a foundation or pilings or lying on the ground in earth-fast construction and bearing the upright portion of a frame. Also spelled cill. Also called a ground plate, groundsill, sole, sole-plate, mudsill. An interrupted sill fits between posts instead of being below and supporting the posts in timber framing.
  3. A horizontal layer of igneous rock between older rock beds.
  4. A piece of timber across the bottom of a canal lock for the gates to shut against.

Noun (etymology 2)

  1. A young herring.

Noun (etymology 3)

  1. The shaft or thill of a carriage.


The above text is a snippet from Wiktionary: sill
and as such is available under the Creative Commons Attribution/Share-Alike License.

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