sentinel

Meanings

1. A sentry, watch, or guard.
2. A private soldier.
3. A unique value recognised by a computer program for processing in a special way, or marking the end of a set of data.
4. A sentinel crab.
5. A sign of a health risk (e.g. a disease, an adverse effect).

1. To watch over as a guard.
2. To post a guard for.

1. A place in the United States:
2. An unincorporated community in Maricopa County, Arizona.
3. A ghost town in Fresno County, California.
4. An unincorporated community in Polk County, Missouri.
5. A town in Washita County, Oklahoma.

Etymology

1570s, from Middle French sentinelle, from Old Italian sentinella (perhaps via a notion of "perceive, watch", compare Italian sentire (“to feel, hear, smell”)), from Latin sentiō (“feel, perceive by the senses”). See sense, sentient.