(1):

(a.) Steadiness or firmness of character, firmness of resolution or purpose; the quality opposite to fickleness, irresolution, or inconstancy; constancy; steadfastness; as, a man of little stability, or of unusual stability.

(2):

(a.) Fixedness; - as opposed to fluidity.

(3):

(a.) The state or quality of being stable, or firm; steadiness; firmness; strength to stand without being moved or overthrown; as, the stability of a structure; the stability of a throne or a constitution.