FROM STRONG’S GREEK DICTIONARY (1890)

Strong’s Greek Dictionary (1890) — public domain, printed whole.

sphragizo σφραγίζω — sfrag-id'-zo — from 4973; to stamp (with a signet or private mark) for security or preservation (literally or figuratively); by implication, to keep secret, to attest:--(set a, set to) seal up, stop.

see GREEK for 4973