El cuñado: The brother-in-law. Los cuñados: The brothers-in-law.
La cuñada: The sister-in-law. Las cuñadas: The sisters-in-law.
El yerno: The son-in-law. Los yernos: The sons-in-law.
La nuera: The daughter-in-law. Las nueras: The daughters-in-law.
El árbol: The tree. Los árboles: The trees.
El examen: The examination. Los exámenes: The examinations.
El lápiz: The pencil. Los lápices: The pencils.
El ómnibus: The omnibus. Los ómnibus: The omnibuses.
El jabalí: The boar. Los jabalíes: The boars.


3. Nouns ending in _Y_ add =Es=, as--

El rey: The king. Los reyes: The kings.
La ley: The law. Las leyes: The laws.

4. The following add only =S= to form the plural--

Papá, Mamá, Bajá (a pasha), Sofá (sofa).[23]

[Footnote 23: Words ending in accented vowels are very few and the rule
for those ending in _á, ó, ú_ is not very strict.]


=Compound Nouns= form their plural according to sense, as--

Hijodalgo (a gentleman by birth), literally, "son of something"; _Plu._,
Hijosdalgo (literally, "sons of something ").
Ferrocarril (railway), literally, "iron railroad"; _Plu._, Ferrocarriles
(literally, "iron railroads").