an intricate knot tied by Gordius, the king of Phrygia, and cut by the sword of Alexander the Great after he heard that whoever undid it would become ruler of Asia
any very difficult problem; insoluble in its own terms
a question raised for consideration or solution; "our homework consisted of ten problems to solve"
a state of difficulty that needs to be resolved; "she and her husband are having problems"; "it is always a job to contact him"; "urban problems such as traffic congestion and smog"
furnish with a preface or introduction; "She always precedes her lectures with a joke"; "He prefaced his lecture with a critical remark about the institution"
move ahead (of others) in time or space
be the predecessor of; "Bill preceded John in the long line of Susan's husbands"
come before; "Most English adjectives precede the noun they modify"