Quercus ilex, the Holm Oak or Holly Oak is a large evergreen oak native to the Mediterranean region. It takes its name from holm, an ancient name for holly. It is known by the names azinheira in Portuguese, encina in Spanish, carrasca in Aragonese, or alzina in Catalan, PIRNAL MEŞESİ in Turkish,, česvina in Croatian, črničevje in Slovenian, is-siġra tal-ballut in Maltese, sindiyānah (سِنْدِيَانَة) in Arabic and chêne vert or yeuse in French. In Provence it is commonly known as l'eouvé. It is a member of the white oak section of the genus, with acorns that mature in a single summer. It was first Introduced to the United Kingdom in the 17th century. The first trees to be planted from acorns in the United Kingdom are still to be found growing within the stately grounds of Mamhead Park, Devon. They are uncommonly fine examples and several of these trees are ten feet in circumference, at three feet from the ground; and one of them measures thirteen feet six inches in circumference.

Quercus ilex is a medium-size tree 20–27 m tall with finely square-fissured blackish bark and leathery evergreen leaves. The old leaves fall 1–2 years after new leaves emerge. The leaves are dark green above and pale whitish-grey with dense short hairs below. The leaf shape is variable, the adult leaves are entire, 4–8 cm long and 1–3 cm broad, while those on the lower branches of young trees are often larger (to 10 cm long), and are toothed or somewhat spiny - possibly as protection from grazing animals. In this, the foliage resembles that of the common European Holly Ilex aquifolium, and this resemblance has led to its common and botanic names. The name ilex is originally the classical Latin name for the Holm Oak, but was later also used as a botanical genus name for the hollies. The flowers are catkins, produced in the spring; the fruit is an acorn, which matures in about six months.