Definition, synonyms and related words
plural of knee
"When he fell down the stairs, both his knees scraped against the rough pavement."
Third-person singular simple present indicative form of knee
"He does not want to kneel on his knees, but he knows how to properly kneel during prayer."
In plain English: To knees means to fall down on your knees, often because you tripped or lost your balance.
"The baby's knees buckled when he saw his favorite toy fall to the floor."