Definition of "holdfast" [hold•fast]

• Any of various devices used to fasten something securely. (noun)
• Biology An organ or structure of attachment, especially the basal, rootlike formation by which certain seaweeds or other algae are attached to a substrate. (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.

• "But now of the holdfast, which is our special subject."
• ""bench-screw," as it is called; that is, a screw which passes through the bench into the back of the work, which may thus be turned about at will; also, if the work is very thick, they hold it in position by means of a bench "holdfast," a kind of combined lever and screw; but neither of these contrivances is likely to be required by the beginner, whose work should be kept within manageable dimensions."
• "We stopped along the way for (an enormous) brunch at The (infamous) Friendly Toast in Portsmouth New Hampshire, then visited Portland where (after some explorations prompted by missing the ferry because we couldn't find parking) joined yuki_onna and justbeast in their secret island holdfast. chang3002. met us on the ferry."