http://glosarios.servidor-alicante.com/arquitectura_en-es
Eaves board Testero, alero de tablas. (IMO, I don't think this is 100% correct).

http://www.spanishdict.com/answers/132591/how-does-one-defin...

https://es.wikipedia.org/wiki/Testero_(arquitectura)
En arquitectura, el testero, palabra derivada del Latín testa (cabeza), sirve para designar la pared opuesta a la entrada principal. También puede designar en un templo la cabecera opuesta al imafronte.
https://en.wikipedia.org/wiki/Monastery_of_Leyre
The Monastery of San Salvador of Leyre is a religious complex to the south of the Sierra of Leyre, in northern Navarre, Spain, representing one of the most important historical monasteries of Spain. The oldest records of the site date from 842, when Íñigo Arista, considered the first king of Pamplona, and Wilesindo, Bishop of Pamplona, made a donation to the monastery. The monastery grew in importance thereafter, acquiring numerous properties and wealth during the first and middle stages of the Kingdom of Navarre, thanks to the privileges and donations made by the Navarrese kings. The monastery was expanded in the twelfth century. Several kings of Navarre were buried there.

Since then it has been in various states of repair, undergoing many expansions and remodelling (the most extensive carried out in the sixteenth century, when almost the entire monastery was rebuilt). Romanesque architecture pieces have survived until the present day (such as the church, with its Porta Speciosa), as well as parts that are even more ancient such as the notable crypt.

Use of "headwall" in English.
http://ipce.mcu.es/pdfs/PNAbadias_Monasterios_y_Conventos_Co...
The layout of the Cistercian monastery is among the clearest and most rigid. It
is in the apse of the church, as well as in the wing of the cloister corresponding to
the refectory and in the area for lay brothers or converts, where we can see the
greatest novelties.
The church tends to adopt a “T”-shaped plan, with a straight **headwall** in what is
called the “Bernardine ground plan”. It features three naves, with the central one
occupied by the two choirs of fathers and brothers, or monks and converts, with
both of them separated as in the rest of the monastery.

Holy Family: a variant comprised of Saint Anne, the Virgin and
Child, situated in the niche in the centre of the headwall across
from the entrance door to the choir.

SANTA MARÍA DE WAMBA - Turismo Prerrománico
www.turismo-prerromanico.com/.../santa-mara-de-wamba-201305...
It is believed Vista del testero mozárabe desde el Sudeste ... Besides, the Monastery of Wamba is mentioned in a document of 948. ... against a three rectangular apses sanctuary, the central one protruding in the headwall. ... from the clergy, mandatory in the cult of Visigothic Spain that is now defined as Mozarabic lithurgy.
Dictionary Spanish-English - Linguee
www.linguee.com/spanish-english/.../una fachada a la calle....
el testero principal para presentar una fachada frontal a la calle principal, cuyas ... The main headwall has thus been twisted to present a front façade to the main ...

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Note added at 7 hrs (2015-09-13 15:10:36 GMT)
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https://en.wikipedia.org/wiki/Church_of_San_Martín_de_Luiña
Description of Architecture
The building has a masonry foundation, with ashlar stone columns in each corner, and has features such as chains, windows, buttresses, pillars, arches, transoms, cornices and ornamental features such as corbels. The exterior walls are plastered and whitewashed. The church has a Latin-cross plan with three naves, flat headers, with lateral vestries and a bell tower at the foot, the ***headwall**** appears attached to the former parish cemetery, today a garden. The nave and transept have a vaulted ceiling, the apse has a slightly pointed barrel vault ceiling and the central section of the hemispherical dome has scalloped decorations.

http://ondiseno.com/proyecto_en.php?id=1598
BARCELONA
Mediapro Tower. Distrito 22
The building’s volumetric composition has been formed by following the alignments and visual guidelines of its urban position. The main **headwall** has thus been twisted to present a front façade to the main street, whose first four floors have been perforated to provide an exit to calle Bolivia, thus giving focus to its urban perspective. The tower, with its first cantilevered shift, builds an edge that brings tension and character to the complex. In the upper floors, the building seeks the upper edge of the tower on a diagonal, finishing off its geometry in a sculptural manner and generating a dynamic play of shadows through the interaction of the two alignments.