sedimentary

American  

[sed-uh-men-tuh-ree] / ˌsɛd əˈmɛn tə ri /

Sometimes sedimental

adjective

1. of, relating to, or of the nature of sediment.

2. Geology. formed by the deposition of sediment, as certain rocks.

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sedimentary British  

/ ˌsɛdɪˈmɛntərɪ /

adjective

1. characteristic of, resembling, or containing sediment

2. (of rocks) formed by the accumulation and consolidation of mineral and organic fragments that have been deposited by water, ice, or wind Compare igneous metamorphic

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sedimentary Scientific  

/ sĕd′ə-mĕn′tə-rē /

1. Relating to rocks formed when sediment is deposited and becomes tightly compacted. Depending on the origin of the sediments they contain, sedimentary rocks are classified as clastic sedimentary rocks, chemical sedimentary rocks, or evaporites. Sandstone and conglomerate, for example, consist of fragments of broken preexisting rocks or minerals and are classified as clastic sedimentary rocks. Limestone forms from the precipitation of calcium carbonate through water and is classified as a chemical sedimentary rock. Gypsum and halite deposits form through the evaporation of mineral-rich water and are classified as evaporites.

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Other Word Forms

• sedimentarily adverb
• unsedimentarily adverb
• unsedimentary adjective

Etymology

Origin of sedimentary

First recorded in 1820–30; sediment + -ary

Explanation

Anything sedimentary is formed by or resembles sediment, which consists of little particles of earth that collect in natural bodies of water. If you ever walked in a lake barefoot and felt the grainy, rocky bottom of the lake, you know how sedimentary things feel. Sedimentary is also a type of rock that’s made from substances left from wind, water, or ice and have been pressed together over time. The other types of rock are igneous (made from lava) and metamorphic (changed from intense heat and pressure). Sedimentary things generally hang out at the bottom of lakes and ponds.

Example Sentences

A slab of sedimentary rock was covered in a wrinkled texture that looked strikingly like elephant skin.

From Science Daily • Apr. 3, 2026

Shale is, after all, the most common sedimentary rock and found all over the world.

From The Wall Street Journal • Feb. 10, 2026

At the top there is, like frosting on a cake, shale mud, Altamira Shale, the sedimentary legacy of those seabed millennia.

From Los Angeles Times • May 3, 2024

A research team at Tsinghua University in China also calls plastistone “an emerging type of sedimentary rock.”

From Slate • Apr. 27, 2024

In the event, the sedimentary layer was 50 percent deeper than expected and the basaltic layer was never found at all.

From "A Short History of Nearly Everything" by Bill Bryson