OA

1 of 2

abbreviation (1)

osteoarthritis

OA … usually occurs after age 45 and involves "wear and tear" on the joints.—

Andrew Weil

o/a

2 of 2

abbreviation (2)

on or about

Browse Nearby Words

o/a

OAA

See all Nearby Words

Cite this Entry

Style

“OA.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/OA. Accessed 14 Feb. 2026.

Copy Citation

Medical Definition

abbreviation

osteoarthritis

Popular in Grammar & Usage

More Words You Always Have to Look Up

'Buck naked' or 'butt naked'?

What does 'etcetera' mean?

The Difference Between 'i.e.' and 'e.g.'

What’s the difference between ‘cemetery’ and ‘graveyard’?

Popular in Wordplay

OA

abbreviation (1)

abbreviation (2)

Browse Nearby Words

Cite this Entry

Medical Definition

More from Merriam-Webster

Word of the Day

canoodle

Popular in Grammar & Usage

More Words You Always Have to Look Up

'Buck naked' or 'butt naked'?

What does 'etcetera' mean?

The Difference Between 'i.e.' and 'e.g.'

What’s the difference between ‘cemetery’ and ‘graveyard’?

Popular in Wordplay

16 Glee-ridden Words from Schitt's Creek

Did Orange the Fruit or the Color Come First?

Why Is the Letter ‘Z’ Associated With Sleeping?

The Words of the Week - Feb. 13

Why do we call it 'ides of March'?

Popular

More Words You Always Have to Look Up

16 Glee-ridden Words from Schitt's Creek

Did Orange the Fruit or the Color Come First?

Games & Quizzes