Definition of "azoic" [a•zo•ic]

• Of or relating to geologic periods that precede the appearance of life. (adjective)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Scientists long ago clung to the "azoic hypothesis" about the deep -- the presumption that nothing could possibly be alive so far from the photosynthetic world."
• "They imagined they could distinguish certain geological relations and families, and would talk about trilobites, the Old Red Sandstone period, and the azoic age, or follow random speculation to far-lying conclusions, developing vague humors of phrase and fancy, having altogether a joyful good time."
• "Plutonic action would be very general, and volcanic mud, ash, and sand would be ejected and spread far and wide, which, sinking to the bottom of the water, may possibly be the origin of what we now designate the azoic or metamorphic slates and schists, as also the early Cambrian and Silurian strata."