Aver
Aver (ā"vẽr) , noun
[Old French aver domestic animal, whence Late Latin averia, pl. cattle. See Habit, and compare Average.]
A work horse, or working ox. [Obsolete or Dialectal English]
Aver (ȧ*vẽr") , transitive verb
[French avérer, Late Latin adverare, averare; Latin ad + versus true. See Verity.]
1.
To assert, or prove, the truth of. [Obsolete]
2.
(Law) To avouch or verify; to offer to verify; to prove or justify. See Averment.
3.
To affirm with confidence; to declare in a positive manner, as in confidence of asserting the truth.
It is sufficient that the very fact hath its foundation in truth, as I do seriously aver is the case.
Then all averred I had killed the bird.