Which pharmacological abbreviation means "twice a day"?

The abbreviation that specifically means "twice a day" is b.i.d., which stands for "bis in die" in Latin. This term is commonly used in healthcare to instruct that a medication should be taken two times within a 24-hour period. Understanding these abbreviations is vital for accurately following medication administration guidelines and for clear communication among healthcare providers.

In contrast, t.i.d. stands for "three times a day," indicating that a medication should be administered three times throughout the day. The abbreviation q.i.d. means "four times a day" and signifies that a medication should be taken four times within a day. The abbreviation q.4.h. translates to "every four hours," which specifies the timing of administration but does not equate to the frequency of twice a day. This context helps clarify why b.i.d. is the correct choice.