Abarim Publications' online Biblical Greek Dictionary
The preposition δια (dia) means through or throughout. Connected to appropriate verbs it may express the traversing of a place, or the experiencing of a time period. It may be used to indicate the instrument with which something is brought about (by means of, or via) or the mode, manner or circumstances (on account of) and even for what reason or out of which motivation. As prefix, δια (dia) is also used to indicate a measure of permeation, dispersal or scattering, as in the word diaspora.