What does ā stand for in medical abbreviations?

The ā medical abbreviation means before.

Explanation:

The ā (a with bar over it, coming from the Latin word "ante")

An example would be:

Omeprazole 40 mg/tab, 1 tab po od ā. am meal

Take 1 tab of Omeprazole 40 mg once a day before AM meal or breakfast.

But the use of a. c. (before meals) or q. a. m. (every morning) is more acceptable.

"ante" is used as a prefix to indicate "before" or "in front of" as in antecedent and antique.

Answer: before

Explanation: As in taking medicine before a meal.