hold·​fast ˈhōl(d)-ˌfast How to pronounce holdfast (audio)
plural holdfasts
: something to which something else may be firmly secured
Fire damage has revealed metal holdfasts used to attach … to the brickwork …Harriet Sherwood
(figurative) But leaders also need personal moorings and holdfasts that help guide tough choices and the consequences that ensue.Chad Blair
: a rootlike part by which a usually aquatic organism (such as an alga or sponge) clings to a substrate
During storms—and occasionally when sea urchins eat through a holdfast—whole kelp plants can become detached, rising to the surface where they form free-floating rafts.Alistair Hobday
… an external network of holdfasts that anchor the individual mussel to the substrate.Douglas Smith
Clinging vines can attach themselves to flat surfaces using aerial roots growing from their stems or special structures called holdfasts.Dan Gill
: an organ by which a parasitic animal (such as a tapeworm) attaches itself to its host
After parasitic worms reach their final habitats, there must be some mechanism to keep them there. … The most effective and economical method to resist these flows is to use an attachment organ or holdfast.Michael V. K. Sukhdeo

Example Sentences

Recent Examples on the Web Then her beauty acted like a mooring for her other outward qualities, undulating from that holdfast like fronds of kelp on the sea. Jeff Wheelwright, Discover Magazine, 20 May 2012 Trilobites would scuttle across the ocean floor past primitive sea anemones gripping the bottom with their fleshy holdfasts. Michael Greshko, National Geographic, 21 Mar. 2019 State rules required cutters to trim above the lowest branches and no closer than 40 centimeters from the holdfast—the sturdy foot with which rockweed grips the shore—to allow the plants to regrow after each haircut. Ben Goldfarb, Smithsonian, 31 May 2018 The vine also produces holdfasts, and is consequently an excellent tree climber, growing aggressively upward, eventually strangling its host. Dave Taft, New York Times, 20 Jan. 2017

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'holdfast.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1566, in the meaning defined at sense 1

Time Traveler
The first known use of holdfast was in 1566

Dictionary Entries Near holdfast

Cite this Entry

“Holdfast.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/holdfast. Accessed 7 Jun. 2023.

Kids Definition


hold·​fast ˈhōl(d)-ˌfast How to pronounce holdfast (audio)
: a part by which a plant (as a seaweed) or animal (as a tapeworm) clings (as to a flat surface or the body of a host)

Medical Definition


hold·​fast ˈhōl(d)-ˌfast How to pronounce holdfast (audio)
: an organ by which a parasitic animal (as a tapeworm) attaches itself to its host

More from Merriam-Webster on holdfast

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