Probably strengthened from G5420; a signet (as fencing in or protecting from misappropriation); by implication the stamp impressed (as a mark of {privacy} or {genuineness}) literally or figuratively: - seal.
Neuter of a presumed derivative probably of the same as σφαῖρα sphaira (a {ball}sphere; compare the feminine σφῦρα sphura {} a hammer); the ankle (as globular): - ancle bone.