Bible Dictionary
WATCH
A watch was a division of the night, first into three periods and later into four. The word can also mean a guard, the act of guarding, or spiritual restraint and vigilance.
Definition
A watch may be a division of the night, a guard assigned to watch, the act of guarding, or a means of restraint and vigilance. Biblical night watches were periods assigned for observation and protection.
Biblical Usage
The figurative use includes the prayer, “Set a watch ... before my mouth,” meaning restraint over speech. The New Testament also refers to watches as divisions of the night and as guards.
Historical Background
The night was first divided into three watches, but later into four according to the Roman system, each occupying a fourth of the night. Watch could also mean a military guard or a period of duty.
Historical Bible Dictionaries
International Standard Bible Encyclopedia (ISBE)
<p>woch ('ashmurah, 'ashmoreth; phulake): A division of the night. The night was originally divided into three watches (Jud 7:19), but later into four, as we find in the New Testament (Mt 14:25; Mr 6:48). We do not know the limits of the watches in the first division, but the middle watch probably began two hours before midnight and ended two hours after. The fourfold division was according to the Roman system, each of which was a fourth part of the night.</p><p>See TIME.</p><p>"Watch" is also the guard placed on watch (mishmar, Ne 4:9; koustodia, from Latin custodia, Mt 27:65,66; 28:11). It sometimes refers to the act of watching, as in 2Ki 11:6,7 (mishmereth); Lu 2:8 (phulake).</p><p>"Watch" is also used figuratively, as in Ps 141:3 for restraint: "Set a watch, O Yahweh, before my mouth" (shomrah).</p><p>See WARD.</p><p>H. Porter</p>