N400 or N-400 may refer to:
*
N400 (neuroscience), an event-related potential component elicited by meaningful stimuli (words, pictures, etc.)
*
N-400 road (Spain)
The N-400 is a highway in Spain from Toledo to Cuenca. It is being upgraded to the Autovía A-40, section by section.
It starts at the junction of the N-401, and the Autovía A-42 east of Toledo.
It heads east to Aranjuez and the Autopista R- ...
, a highway connecting Toledo to Cuenca
*
Honda N400, a car similar to the Honda N360
* Samsung N400, a mobile phone by
Samsung
*
Form N-400,
United States Citizenship and Immigration Services application for naturalization
* A variant of the
Aston Martin V8 Vantage car
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