1) a fortified place provided with a garrison, a station for a
    guard or garrison
 2) a preservative or safeguard , an amulet. The Jews used this word
    to describe small strips of parchment on which were written the
    following passages of the law of Moses, Ex. 13:1-10, 11-16; Dt.
    6:4-9, 11:13-21, and which, enclosed in small cases, they were
    accustomed when engaged in prayer to wear fastened by a leather
    strap to the forehead and to the left arm over against the heart,
    in order that they might thus be solemnly reminded of the duty of
    keeping the commands of God in the head and in the heart,
    according to the directions given in Ex. 13:16, Dt. 6:8, 11:18;
    These scrolls were thought to have the power, like amulets, to
    avert various evils and to drive away demons. The Pharisees were
    accustomed to widen, make broad, their phylacteries, that they
    might render them more conspicuous and show themselves to be more
    eager than the majority to be reminded of the law of God.