first-line

American  

[furst-lahyn] / ˈfɜrstˈlaɪn /

adjective

1. available for immediate service, especially combat service.

   first-line troops.

2. of prime importance or quality.

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first-line British  

adjective

1. acting or used as a first resort

   first-line treatment

   first-line batsmen

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Etymology

Origin of first-line

First recorded in 1895–1900

Example Sentences

Each time, the first-line representative said no, suggesting something like, “If you can’t afford to pay it now, set up a payment plan or apply for financial assistance.”

From Slate • Apr. 25, 2026

They were given the RP1 oncolytic virus therapy, in addition to an anti-PD-1 immunotherapy that is a first-line melanoma treatment.

From The Wall Street Journal • Apr. 21, 2026

Nektar stock jumped 26% after positive trial results, with analysts raising price targets and expecting first-line treatment potential.

From Barron's • Apr. 20, 2026

For over 60 years, metformin has been a first-line treatment for type 2 diabetes, yet scientists have not fully understood how it works.

From Science Daily • Mar. 25, 2026

The Peruvian doctors were following WHO protocol, retreating Christian with standard first-line antibiotics that had failed to stop the TB in the first place.

From "Mountains Beyond Mountains" by Tracy Kidder and Michael French