Asherah: a Canaanite mother-goddess, and the wooden pole or stylized tree set up at a worship site to represent her
This one word names two things that the people who used it did not separate: a goddess and the wooden symbol that stood for her. Asherah was a high goddess of the wider Canaanite world long before Israel existed, the partner of the chief god El and called the mother of the gods. Her name carried into Hebrew unchanged, and a wooden object that bore that name, a planted pole or a shaped tree, stood beside altars across Israel and Judah, sometimes even in the Jerusalem temple.
The Hebrew text lets the same word point now at the living goddess, now at the wood. When the text speaks of prophets of Asherah or a carved image of Asherah, a person is in view, because you cannot make a carved image of a mere pole. When the text speaks of planting, cutting down, or burning an asherah, the wooden object is in view. Most often the two cannot be cleanly pulled apart, because the object was the goddess's stand-in and was treated as if she were present in it.
The Bible itself shows the word changing over time. In the oldest layer an asherah simply stands at a local altar with no apology. The law then forbids planting one beside the LORD's altar. The history books judge each king by whether he set one up or tore it down, and the prophets finally use the word as a stock label for forbidden worship. By the time the Old Testament was translated into Greek, the goddess behind the word had been so thoroughly buried that the translators usually rendered it simply grove, and her identity was only recovered in modern times.