Definition "complex" in Collins English Dictionary & Thesaurus, spelling "complex"

complex (complexes plural )
The adjective is pronounced [PH:k][PH:&][PH:m][PH:p][PH:l][PH:e][PH:k][PH:s] in American English.

1 adj Something that is complex has many different parts, and is therefore often difficult to understand. (=complicated) (Antonym: simple) ...in-depth coverage of today's complex issues., ...a complex system of voting., ...her complex personality., ...complex machines.

2 adj In grammar, a complex sentence contains one or more subordinate clauses as well as a main clause. Compare compound.
ADJ n

3 n-count A complex is a group of buildings designed for a particular purpose, or one large building divided into several smaller areas.
usu with supp
...plans for constructing a new stadium and leisure complex., ...a complex of offices and flats.

4 n-count If someone has a complex about something, they have a mental or emotional problem relating to it, often because of an unpleasant experience in the past.
I have never had a complex about my height., ...a deranged attacker, driven by a persecution complex.
→ guilt complex
→ inferiority complex