From BiblePortal Wikipedia

Charles Buck Theological Dictionary [1]

Is a virtue or quality of the mind generally considered the same with courage; though, in a more accurate sense, they seem to be distinguishable. Courage resists danger, fortitude supports pain. Courage may be a virtue or vice, according to the circumstances; fortitude is always a virtue: we speak of desperate courage, but not of desperate fortitude. A contempt of neglect of danger may be called courage; but fortitude is the virtue of a rational and considerate mind, and is founded in a sense of honour, and a regard to duty. Christian fortitude may be defined that state of mind which arises from truth and confidence in God; enables us to stand collected and undisturbed in the time of difficulty and danger; and is at an equal distance from rashness on the one hand, and pusillanimity on the other. Fortitude takes different names, according as it acts in opposition to different evils; but some of those names are applied with considerable latitude.

With respect to danger in general, fortitude has been called intrepidity; with respect to the dangers of war, valour; with respect to pain of body, or distress of mind, patience; with respect to labour, activity; with respect to injury, forbearance; with respect to our condition in general, magnanimity. Christian fortitude is necessary to vigilance, patience, self-denial, and perseverance; and is requisite under affliction, temptation, persecution, desertion, and death. The noble cause in which the Christian is engaged; the glorious Master whom he serves; the provision that is made for his security; the illustrious examples set before him; the approbation of a good conscience; and the grand prospect he has in view, are all powerful motives to the exercise of this grace. Watts's Ser. ser. 31. Evan's Ser. ser. 19. vol. 1: Steele's Christian Hero; Mason's Ser. vol. 1: ser. 5:

Webster's Dictionary [2]

(1): ( n.) Power to resist attack; strength; firmness.

(2): ( n.) That strength or firmness of mind which enables a person to encounter danger with coolness and courage, or to bear pain or adversity without murmuring, depression, or despondency; passive courage; resolute endurance; firmness in confronting or bearing up against danger or enduring trouble.