Reef \Reef\, v. t. [imp. & p. p. Reefed (r[=e]ft); p. pr. & vb. n. Reefing.]

(Naut.) To reduce the extent of (as a sail) by roiling or folding a certain portion of it and making it fast to the yard or spar. --Totten.

To reef the paddles, to move the floats of a paddle wheel toward its center so that they will not dip so deeply.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Reefing \Reef"ing\, n. (Naut.) The process of taking in a reef.

Reefing bowsprit, a bowsprit so rigged that it can easily be run in or shortened by sliding inboard, as in cutters.

Source: Webster's Revised Unabridged Dictionary (1913)