- Zoology An elongated flexible unsegmented extension, as one of those surrounding the mouth or oral cavity of the squid, used for feeling, grasping, or locomotion. (noun)
- Botany One of the sensitive hairs on the leaves of insectivorous plants, such as the sundew. (noun)
- A similar part or extension, especially with respect to the ability to grasp or stretch: an espionage network with far-reaching tentacles. (noun)
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.