From BiblePortal Wikipedia

Webster's Dictionary [1]

(1): ( n.) A central point; a point of concentration.

(2): ( n.) A point in which the rays of light meet, after being reflected or refrcted, and at which the image is formed; as, the focus of a lens or mirror.

(3): ( n.) A point so related to a conic section and certain straight line called the directrix that the ratio of the distace between any point of the curve and the focus to the distance of the same point from the directrix is constant.

(4): ( v. t.) To bring to a focus; to focalize; as, to focus a camera.

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [2]

the ancient Roman hearth, which was dedicated to the Lares (q.v.) of each family. The domestic hearth was looked upon with such veneration that to swear by the royal hearth was accounted the most sacred oath among the Scythians. On the occasion of religious festivals the hearth was adorned with garlands.