sentinel

IPA: sˈɛntʌnʌɫ

A sentry, watch, or guard.
(obsolete) A private soldier.
(computer science) A unique value recognised by a computer program for processing in a special way, or marking the end of a set of data.
A sentinel crab.
(attributive, medicine, epidemiology) A sign of a health risk (e.g. a disease, an adverse effect).
(figuratively) Someone who is hardworking and dutiful.
A ghost town in California.
A town in Oklahoma.

Examples of "sentinel" in Sentences

I do have a veterinarian friend who has what he calls a sentinel cat.
It's appropriately called the sentinel node, and they found no cancer.
Complete lymph-node surgery has been the most common procedure for women whose cancer has reached certain lymph nodes called sentinel nodes.
"Oh, this isn't a co-op exactly, and it's not like, uh, the Guardian Angels, except for what they call sentinel stance, and - It's sort of like a church, except not that either.
These days, Spencer is busier than usual: she's moonlighting as a "sentinel" -- one of 80 or so doctors who sends a regular tally of fevers and raspy coughs to New York City's health department.
Any inflation will probably show up in the property market first and can be dealt with by a simple land value tax, possibly the so-called sentinel tax triggered by upwards movements in land prices.
Lieutenant Hayward treated him with a sort of contemptuous look, and began to enter into conversation with him respecting the _Bounty_, but I called the sentinel in to take them into custody, and ordered Lieutenant
The biopsy procedure known as sentinel lymph node SLN dissection has been praised for averting the removal of large numbers of armpit lymph nodes during breast cancer surgery, which can lead to a painful buildup of fluid called lymphedema.