re·flex (rē'flĕks')
adj.

1. Bent, turned, or thrown back; reflected.
2. Physiology. Being an involuntary action or response, such as a sneeze, blink, or hiccup.
3. Produced as an automatic response or reaction: reflex opposition to change.

n.

1. 1. Something, such as light or heat, that is reflected.
   2. An image produced by reflection.
   3. A copy or reproduction.
2. Physiology. An involuntary response to a stimulus.
3. Psychology. An unlearned or instinctive response to a stimulus.
4. Linguistics. A form or feature that reflects or represents an earlier, often reconstructed, form or feature having undergone phonetic or other change.

tr.v., -flexed, -flex·ing, -flex·es. (rĭ-flĕks')

1. To bend, turn back, or reflect.
2. To cause to undergo a reflex process.

[From Middle English reflexen, to refract light, bend back, from Latin reflexus, past participle of reflectere, to bend back. See reflect.]

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The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.

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