Judgment_paragraph 42 · Z. Zh. v Staatssecretaris van Veiligheid en Justitie and Staatssecretaris van Veiligheid en Justitie v I. O (C-554/13)

42It is settled case-law that the meaning and scope of terms for which EU law provides no definition must be determined by considering their usual meaning in everyday language, while also taking into account the context in which they occur and the purposes of the rules of which they are part. When those terms appear in a provision which constitutes a derogation from a principle, they must be read so that that provision can be interpreted strictly. Furthermore, the preamble to a European Union measure may explain the measure’s content (see, to that effect, judgment in Wallentin-Hermann, C‑549/07, EU:C:2008:771, paragraph 17 and the case-law cited).