Definition

1. Noun:
   • (Geology) A flat, typically horizontal sheet or layer of igneous rock that has been forced between older layers of sedimentary rock or other material.
   • (Construction/Architecture) A horizontal structural member, typically made of wood, stone, or metal, that forms the base or bottom part of a framework, such as the lowest part of a window or door frame.

Usage Examples

• Noun (Geology):

  • The geologist pointed out a thick basalt sill intruding between the limestone layers.
  • Sills are formed when magma cools and solidifies in a crack parallel to the existing rock strata.

• Noun (Construction):

  • The carpenter replaced the rotten wooden sill beneath the window.
  • Water had pooled on the stone sill of the old castle window.

Advanced Usage

• "Window sill" (Compound Noun): The horizontal ledge at the bottom of a window, often inside a building.

  • She placed the flower pot on the sunny window sill.

• "Door sill" or "Threshold" (Compound Noun): The horizontal piece forming the bottom of a doorway.

  • He stepped over the door sill and entered the house.

Variants and Related Words

• Sill plate (n): In construction, the bottom horizontal member of a wall or structure to which vertical studs are attached.

  • The sill plate must be properly treated to prevent rot.

• Lintel (n): A horizontal support across the top of a door or window (contrasts with a sill, which is at the bottom).

  • The stone lintel above the door was carved with ancient symbols.

Synonyms

• Geology: Sheet, intrusion, layer.
• Construction: Ledge, base, threshold (for door sills).

Related Phrases

• "To be on the sill of": (Figurative) To be at the very beginning or edge of something.
  • The country stood on the sill of a new era. (Note: This is a less common, literary usage.)

Notes on Usage

• In everyday language, "sill" is most commonly used in the compound forms "window sill" or "door sill". When used alone in a construction context, it is often clear from the situation (e.g., "the sill is rotting" implies a window or door sill).
• In geology, "sill" is a specific technical term and is not used in compound forms.

Noun

1. (geology) a flat (usually horizontal) mass of igneous rock between two layers of older sedimentary rock
2. structural member consisting of a continuous horizontal timber forming the lowest member of a framework or supporting structure