“Maacah, the grandmother.” Maacah was the wife of Rehoboam, the grandfather of Asa, and so Maacah was the grandmother of Asa. The Hebrew does not have a specific word for “grandmother,” but uses “mother” and expects people to know the correct genealogy.

“queen mother.” The Hebrew word (Strong’s #01377) refers to the “queen mother,” who in this context is the grandmother of the king (BDB Hebrew and English lexicon). The queen mother was the most powerful woman in the kingdom, much more powerful than any of the wives of the king, who often did not have much real power at all. In this case, the “queen grandmother” was ungodly and Asa removed her from her powerful position, but the text does not tell us how he did that.

“in the brook Kidron.” The brook Kidron ran dry most of the year.