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

Molecular biologist Soulama says that Burkina Faso has decided, like some other countries on the continent, to move toward multiple first-line therapies. — Christine Ro, Forbes.com, 23 July 2026

Zidesamtinib is also being explored as a first-line treatment. — Meghana Keshavan, STAT, 23 July 2026

Cognitive behavioral therapy for insomnia, known as CBT-I, is considered the first-line treatment for chronic insomnia. — Hanna Wickes, Fort Worth Star-Telegram, 17 July 2026

For instance, if a patient with obesity is diagnosed with hypogonadism and no other condition explains the low testosterone levels (such as a pituitary tumor), the first-line treatment is weight loss. — Beth Mole, ArsTechnica, 17 July 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