pillow lava

American  

noun

Geology.

1. lava in the form of an agglomeration of rounded, pillow-shaped masses, the result of subaqueous or subglacial volcanic eruption.

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pillow lava British  

noun

1. lava that has solidified under water, having a characteristic structure comprising a series of close-fitting pillow-shaped masses

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pillow lava Scientific  

/ pĭl′ō /

1. Lava that forms from an underwater eruption and is characterized by pillow-shaped masses. Pillow lava forms when hot lava is suddenly exposed to cold water, forming a sacklike membrane that is filled with additional cooling and solidifying lava. The outer membrane is usually finer grained than the inner lava.

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Etymology

Origin of pillow lava

First recorded in 1900–05

Example Sentences

I swear my heart nearly stopped beating the first time I saw it: a mountain of pillow lava atop another mountain.

From Scientific American

A deep sea fish swims over a pillow lava field on the Galápagos Rift.

From National Geographic

Massive pillow lava flows came into sight and the pilots had to be careful to avoid overhanging rock walls and ledges as they started to move up the flanks of the seamount.

From Scientific American

A deep sea fish swims over a pillow lava field on the Galápagos Rift.

From National Geographic

A deep sea fish swims over a pillow lava field on the Galápagos Rift.

From National Geographic