a group or system of different things that are linked in a close or complicated way; a network

a complex of mountain roads

a related group of repressed or partly repressed emotionally significant ideas which cause psychic conflict leading to abnormal mental states or behaviour

an ion or molecule in which one or more groups are linked to a metal atom by coordinate bonds

two guanine bases can attach themselves to the same platinum atom, forming a stable complex

make (an atom or compound) form a complex with another

the DNA was complexed with the nuclear extract