best friend

noun

plural best friends

1

: a person's closest and dearest friend

She's my best friend.

We have been best friends since high school.

2

: a person's most desirable or valuable possession or resource

Diamonds may be a girl's best friend, but gold is more affordable.

—William Giese

Lycra-cotton leggings and tunic tops are the pregnant woman's best friend, sartorially speaking.

—Anne Reeks

When cops bang on the door, the toilet is a drug dealer's best friend.

—Frederick Kaufman

Examples of best friend in a Sentence

Recent Examples on the Web

Aira, Matthew’s best friend, won enough of them over for the boondoggle to proceed: What had the group been, in this last decade or so, but an ailing patient, every so often given new breath by a company member’s ministrations—a lifelong ambition for a part, for example? —Han Ong, New Yorker, 22 June 2025

And so, emboldened, Allie and her best friend from high school, Carol Wilber, joined their brothers and began livestreaming on TikTok, too. —Avery Stone, HollywoodReporter, 20 June 2025

This is season 2, which my wife has already watched, and I’m struck by how little drama there is behind the scenes, as all the girls feel like best friends, for the most part. —Paul Tassi, Forbes.com, 20 June 2025

His best friend moves away, triggering a spiritual and emotional awakening that leads to rebellion and transformation. —Anna Marie De La Fuente, Variety, 20 June 2025

Word History

First Known Use

13th century, in the meaning defined at sense 1

Phrases Containing best friend

• man's best friend

Rhymes for best friend

• amend
• append
• ascend
• attend
• backend
• befriend
• boyfriend
• commend
• compend
• contend
• defend
• depend