What is "triatic stay"

Stay \Stay\ (st[=a]), n. [AS. st[ae]g, akin to D., G., Icel., Sw., & Dan. stag; cf. OF. estai, F. ['e]tai, of Teutonic origin.] (Naut.) A large, strong rope, employed to support a mast, by being extended from the head of one mast down to some other, or to some part of the vessel. Those which lead forward are called fore-and-aft stays; those which lead to the vessel's side are called backstays. See Illust. of Ship.

In stays, or Hove in stays (Naut.), in the act or situation of staying, or going about from one tack to another.
--R. H. Dana, Jr.

Stay holes (Naut.), openings in the edge of a staysail through which the hanks pass which join it to the stay.

Stay tackle (Naut.), a tackle attached to a stay and used for hoisting or lowering heavy articles over the side.

To miss stays (Naut.), to fail in the attempt to go about.
--Totten.

Triatic stay (Naut.), a rope secured at the ends to the heads of the foremast and mainmast with thimbles spliced to its bight into which the stay tackles hook.

n. (context nautical English) A stay connecting the mastheads of a multi-masted rig such as a schooner or ketch.