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

Pogosian met one of his most important muses, a member of the Saudi royal family and his best friend's mother, at Rihanna's Halloween party. — Stephan Rabimov, Forbes.com, 10 Aug. 2026

Beyond keeping space safe, man’s best friend will be at the forefront of future moon research. — Maria Mocerino, Interesting Engineering, 9 Aug. 2026

My mentor growing up was LaTroy Hawkins, my godfather and one of my dad’s teammates and best friends. — Bryan Hood, Robb Report, 8 Aug. 2026

Another video that has drawn GOP criticism has little to do with political opinion, but instead with man’s best friend. — Claire Carter, The Washington Examiner, 7 Aug. 2026

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