An

an is a preposition meaning "to, towards, for" in Sindarin. In Quenya the preposition means "for" or "because".

When used as a prefix, an- means "by" or "with" in Sindarin.

In Adûnaic an- or 'n- means "of"

References

• The Languages of Tolkien's Middle-earth by Ruth S. Noel
• Hiswelókë's Sindarin Dictionary compiled by Didier Willis