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"Descendencia" is a noun which is often translated as "descendants", and "ascendencia" is a noun which is often translated as "ancestry". Learn more about the difference between "descendencia" and "ascendencia" below.
la descendencia(
deh
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sehn
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dehn
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syah
)A feminine noun is almost always used with feminine articles and adjectives (e.g., la mujer bonita, la luna llena).
1. (progeny)
a. descendants  (plural)
El príncipe expresó reiteradamente su deseo de tener descendencia.The prince repeatedly expressed his desire to have descendants.
la ascendencia(
ah
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sehn
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dehn
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syah
)A feminine noun is almost always used with feminine articles and adjectives (e.g., la mujer bonita, la luna llena).
1. (heritage)
a. ancestry 
Italia da la doble ciudadanía a los extranjeros que puedan probar su ascendencia italiana.Italy grants dual citizenship to foreign born people who can prove Italian ancestry.
a. influence 
Los expresidentes todavía tienen mucha ascendencia sobre el destino del país.Former presidents still have a lot of influence over the fate of the country.
b. ascendancy 
Debemos garantizar la ascendencia de la diplomacia sobre el uso de la fuerza.We must assure the ascendancy of diplomacy over the use of force.