complex
The human brain is a very complex organ.
The human brain has many interconnected parts that make it difficult to fully understand.
Consisting of many different and connected parts; not simple.
The instructions for assembling the furniture were too complex.
The assembly instructions had too many steps and were hard to follow.
Often used to describe systems, processes, or concepts that are difficult to understand due to their many interrelated parts.
A group of similar buildings or facilities with a shared purpose.
The apartment complex was built in the 1980s.
The residential complex consists of multiple apartment buildings constructed in the 1980s.
Commonly used in real estate and urban planning.
An unconscious feeling of dislike or hostility towards someone or something.
She has a complex about her height.
She feels deep-seated insecurity or negative feelings about being short.
In psychology, often used in phrases like 'inferiority complex' or 'Oedipus complex'.
A building or group of buildings designed for a specific use, such as housing or industry.
The new shopping complex opened last month.
The recently opened shopping center includes multiple stores and facilities.
Collocations
Related Phrases
Pro Tip
Avoid confusion between noun and adjective forms
Remember that 'complex' as an adjective describes something complicated (e.g., 'a complex problem'), while as a noun it can refer to a group of buildings (e.g., 'a residential complex') or a psychological issue (e.g., 'an inferiority complex'). Context determines the meaning.
Gold Rule
Use 'complex' for interconnected parts, 'complicated' for difficulty
Use 'complex' when something has many interrelated parts (e.g., 'the human genome is complex'). Use 'complicated' when something is difficult to understand or deal with due to its complexity or other factors (e.g., 'the instructions were complicated').
Word Origin
From Latin 'complexus', past participle of 'complecti' meaning 'to entwine, encircle, include', from 'com-' (together) + 'plectere' (to weave). The psychological sense emerged in the early 20th century.
Usage Notes
As an adjective, 'complex' is often followed by 'with' (e.g., 'a complex with many layers'). As a noun, it can refer to either a group of buildings or a psychological concept. Avoid confusing the noun 'complex' (meaning a group of buildings or psychological issue) with the adjective 'complex' (meaning complicated).