Mosquito vs. zancudo

In Spanish, both 'mosquito' and 'zancudo' refer to the small, flying insect known for biting and often causing itchy welts. However, their usage varies by region and context.

Mosquito

The word 'mosquito' is a direct borrow from Spanish into English and is widely understood in many Spanish-speaking regions. It generally refers to the small flying insect of the family Culicidae.
Vi un mosquito en la habitación.
(I saw a mosquito in the room.)
Los mosquitos pueden transmitir enfermedades como el dengue.
(Mosquitos can transmit diseases like dengue.)
Compré un repelente para mosquitos.
(I bought a mosquito repellent.)

Zancudo

'Zancudo' is another term used to refer to mosquitoes, particularly in certain parts of Latin America such as Central America, Colombia, and Venezuela. The word emphasizes the insect's long legs.
Cierra las ventanas para que no entren zancudos.
(Close the windows so that mosquitoes don't come in.)
Los zancudos son muy molestos en las noches de verano.
(Mosquitoes are very annoying on summer nights.)
He oído que los zancudos están muy activos después de la lluvia.
(I've heard that mosquitoes are very active after the rain.)

Summary

Both 'mosquito' and 'zancudo' refer to the same insect but are used differently depending on the region. 'Mosquito' is more universally recognized across Spanish-speaking areas, while 'zancudo' is prevalent in specific Latin American countries. Most native speakers understand both terms despite regional preferences.