Cachoeira vs. cascata vs. catarata
Portuguese vocabulary for falling water varies based on the size, shape, and volume of the flow, as well as regional usage between Brazil and Portugal. While cachoeira is the general term in Brazil, cascata suggests a smaller or stepped flow, catarata implies immense volume, and queda-dágua' is a technical descriptor.
Cachoeira
A2This is the most common and generic term for a waterfall in Brazilian Portuguese, traditionally describing a river falling over a distinct rocky ledge. It is widely used in tourism and daily conversation for places suitable for bathing, whereas in European Portuguese, this word is less common and often replaced by specific local terms or cascata for smaller falls.
Nós passamos o fim de semana tomando banho na cachoeira.
(We spent the weekend bathing in the waterfall.)
A cachoeira fica no final daquela trilha longa.
(The waterfall is at the end of that long trail.)
O guia disse que esta cachoeira é segura para crianças.
(The guide said that this waterfall is safe for children.)
Cascata
B1This term refers to a smaller waterfall, one that tumbles down a series of rocky steps (cascading), or an artificial waterfall found in gardens and pools. In European Portuguese, cascata is frequently used as the general term for picturesque waterfalls, while in Brazil, it strictly implies a smaller size or jagged flow.
O hotel construiu uma cascata artificial na piscina.
(The hotel built an artificial waterfall in the pool.)
A água desce em forma de cascata pelas pedras do jardim.
(The water comes down in the form of a cascade over the garden stones.)
Havia uma pequena cascata decorativa no saguão.
(There was a small decorative waterfall in the lobby.)
Catarata
B2This word is reserved for massive, powerful waterfalls with a tremendous volume of water and usually great width. It is almost exclusively used for major geographic landmarks, such as Niagara Falls or Iguaçu Falls, and conveys a sense of grandeur and danger.
As Cataratas do Iguaçu são uma das maravilhas naturais do mundo.
(The Iguaçu Falls are one of the natural wonders of the world.)
O barulho da catarata era tão alto que não conseguíamos conversar.
(The noise of the massive waterfall was so loud that we could not talk.)
Poucos exploradores sobreviveram à descida daquela catarata.
(Few explorers survived the descent of that massive waterfall.)
Summary
To choose the right word, consider the size and context: use cachoeira for a standard natural waterfall (especially in Brazil), cascata for small, stepped, or decorative falls, catarata for massive natural landmarks with huge volume, and queda-dágua' when technically describing the vertical drop.