Hold"fast` (?), n.
1.
Something used to secure and hold in place something else, as a long fiat-headed nail, a catch a hook, a clinch, a clamp, etc.; hence, a support.
"His
holdfast was gone."
Bp. Montagu.
2. Bot.
A conical or branching body, by which a seaweed is attached to its support, and differing from a root in that it is not specially absorbent of moisture.
© Webster 1913.