first-line

adjective

ˈfərst-ˈlīn 

: being the preferred, standard, or first choice

first-line treatment of tuberculosis

compare second-line

Synonyms of first-line

• selected
• select
• favorite
• preferred
• favored

Examples of first-line in a Sentence

surgery is usually not considered a first-line treatment for this type of cancer

Recent Examples on the Web

Today, the 20-minute rule remains one of the foundational pillars of Cognitive Behavioral Therapy for Insomnia (CBT-I) — a treatment that Walker notes the American Academy of Sleep Medicine endorses as the first-line approach for chronic insomnia, ahead of pharmaceutical interventions. — Sharon Brandwein, USA Today, 27 June 2026

Big-time free-agent acquisition, Nikolaj Ehlers, is listed at 6-feet and never really got star-level first-line deployment with the Winnipeg Jets, in part due to concerns about his defensive quality and physical play. — Thomas Drance, New York Times, 15 June 2026

And just as with Bessie and Bluebell, first-line treatment doesn’t always start with a pill. — Pat Beall, Sun Sentinel, 12 June 2026

According to the American College of Cardiology, first-line strategies for managing high blood pressure include quitting smoking, eating a heart-healthy diet, and increasing physical activity. — Fran Kritz, Verywell Health, 4 June 2026

Word History

First Known Use

1919, in the meaning defined above

Rhymes for first-line

• affine
• airline
• align
• aline
• assign
• baseline
• beamline
• benign
• bloodline
• bovine
• brucine
• byline

Medical Definition

first-line

adjective

ˈfərst-ˈlīn 

: being the preferred, standard, or first choice

first-line treatment of advanced breast cancer

compare second-line