knot-hole

n hole in a piece of timber where a knot1(4) has fallen out （木材上的）节孔（节结脱落形成的空洞）.

knock off, knock off (sth), knock out, knock sb down, knock sb out, knock sb/sth over, knock sth back, knock sth in; knock sth into sth, knock sth together, knock up, knock up against, knock-down, knock-kneed, knock-on, knock-out, knock-up, knockabout, knocker, knoll, knot, knotty, know, know about, know better than, know no bounds, know of, know sb. by name, know-all, know-how, knowing, knowingly, knowledgable, knowledge, knowledgeable, knowledgeably, known, known as, knuckle, knuckleduster, knucklehead,