adjective

consisting of many different and connected parts.

a complex network of water channels

compound,composite,compounded,multiplex

noun

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

a complex of mountain roads

network,system,nexus,web,tissue,combination,composite,synthesis,fusion,aggregation

verb

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

the DNA was complexed with the nuclear extract