τέρθριος

A. rope from the end of a sail-yard (τέρθρον), used for reefing, Ar. Eq. 440, cf. Sch. ad loc.; τ. κάλοι Erot., Gal. 19.145.

II. τερθρία πνοή, cited from S. (Fr. 333) in EM 753.7, is there expld. by ὀπισθία, a stern wind, but perh. rather a stiff gale requiring the use of τέρθριοι.