affidavit

af·fi·da·vit   (āf'ĭ-dā'vĭt)    n.  A written declaration made under oath before a notary public or other authorized officer. [Medieval Latin affīdāvit, from third person sing. past tense of Latin affīdāre, to pledge; see affiance.]

affidavit 

Main Entry: af·fi·da·vit
Pronunciation: "a-f&-'dA-v&t
Function: noun
Etymology: Medieval Latin, he/she has pledged faith, third singular perfect of affidare —see AFFIANT
: a sworn statement in writing made esp. under oath or on affirmation before an authorized magistrate or officer —compare DEPOSITION, EXAMINATION