Forthy, for′thi, adv. (Spens.) therefore. [A.S. forthýfor, and thý, instrumental case of thaet, that.]

Fortieth. See Forty.

Fortify, for′ti-fī, v.t. to strengthen against attack with forts, &c.: to invigorate: to confirm:—pa.p. for′tifīed.—adj. Fortifī′able.—ns. Fortificā′tion, the art of strengthening a military position by means of defensive works: the work so constructed: that which fortifies; For′tifier. [Fr. fortifier—Low L. fortificārefortis, strong, facĕre, to make.]

Fortilage, fōr′ti-lāj, n. (Spens.) a fort. [Fortalice.]

Fortissimo. See Forte.

Fortition, for-tish′un, n. principle of trusting to chance. [L. fors, chance.]

Fortitude, for′ti-tūd, n. mental power of endurance: firmness in meeting danger: (obs.) strength, power of resistance or attack.—adj. Fortitū′dinous. [L. fortitudofortis.]

Fortlet, fōrt′let, n. a little fort.

Fortnight, fort′nīt, n. two weeks or fourteen days.—adj. and adv. Fort′nightly, once a fortnight. [Contr. of A.S. féowertýne niht, fourteen nights.]

Fortress, for′tres, n. a fortified place: a defence.—v.t. (Shak.) to guard. [O. Fr. forteresse, another form of fortelesce (q.v. under Fortalice).]