# What "PA" stands for in chemistry.

**URL:** <https://boards.straightdope.com/t/what-pa-stands-for-in-chemistry/219439>\
**Category:** Cecil's Columns/Staff Reports\
**Created:** [December 17, 2003, 1:51am UTC](https://boards.straightdope.com/t/what-pa-stands-for-in-chemistry/219439 "2003-12-17T01:51:17Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Dolphin](https://avatars.discourse-cdn.com/v4/letter/d/779978/32.png) [@Dolphin](https://boards.straightdope.com/u/Dolphin)\
**Post date:** [December 17, 2003, 1:51am UTC](https://boards.straightdope.com/t/what-pa-stands-for-in-chemistry/219439/1 "2003-12-17T01:51:17Z")

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[http://www.straightdope.com/classics/a3\_338b.html](http://www.straightdope.com/classics/a3_338b.html)

I agree the poser of the question probably intended to ask about pH, but in response to the literal question posed in the thread, the abbreviation “p.a.” in chemistry stand for “pro analysi,” or “up to standard.” Some American chemical companies have adopted American Chemical Society (ACS) standards rather than the historical standards, and the abbreviation “p.a.” is less common now than in the past.