ilex in latin means the holm-oak or evergreen oak quercus ilex despite the linnaean classification of ilex as holly as late as the th century in britain the term ilex was still being applied to the oak as well as the holly – possibly due to the superficial similarity of the leaves the name "holly" in common speech refers to ilex aquifolium specifically stems with berries used in christmas decoration by extension "holly" is also applied to the whole genus the origin of the word "holly" is considered a reduced form of old english holeġn middle english holin later hollen the french word for holly houx derives from the old low franconian *hulis middle dutch huls both are related to old high german hulis huls as are low germanlow franconian terms like hülse or hulst these germanic words appear to be related to words for holly in celtic languages such as welsh celyn breton kelenn and irish cuileann