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"La sequía" is a form of "sequía", a noun which is often translated as "drought". "Ovni" is an abbreviation which is often translated as "UFO". Learn more about the difference between "la sequía" and "ovni" below.
la sequía(
seh
-
kee
-
ah
)A feminine noun is almost always used with feminine articles and adjectives (e.g., la mujer bonita, la luna llena).
a. drought 
La gente en estado de pobreza sufre de sequía y hambre.People in poverty suffer from drought and starvation.
ovni(
ohb
-
nee
)An abbreviation is the shortened form of a word or group of words (e.g., "UFO" = "unidentified flying object"; "p." = "page").
a. UFO 
Hay reportes de un ovni volando sobre la isla.There are reports of a UFO flying over the island.
b. flying saucer 
La foto del ovni resultó ser un engaño.The picture of the flying saucer turned out to be a hoax.