Definition of "commoner"

All below them [the peers], even their children, were commoners, and in the eye of the law equal to each other.

1827, Henry Hallam, The Constitutional History of England from the Accession of Henry VII. to the Death of George II. […], volumes (please specify |volume=I or II), London: John Murray, […]

There are to this day fellow-commoners at Queens, and surely such a distinguished commoner as Fuller would have been allowed to remain on that foundation, in which he had spent seven years, in this new capacity. The expense would have been about the same, and the only way in which I can account for his migration is either pique at being passed over, or the friendship of so famed a theologian as Dr. Ward.

1886, Rev. Morris Joseph Fuller, “College Days (Sydney-Sussex). 1629-1631”, in The Life, Times and Writings of Thomas Fuller, D.D.‎, 2nd edition, volume 1, London: S. Sonnenschein, Le Bas & Lowrey, pages 68–69

Much good land might be gained from forests […] and from other commonable places, so as always there be a due care taken that the poor commoners have no injury.

1631, Francis [Bacon], “(please specify |century=I to X)”, in Sylua Syluarum: Or A Naturall Historie. In Ten Centuries. […], 3rd edition, London: […] William Rawley; [p]rinted by J[ohn] H[aviland] for William Lee […]

From the Counsell he was carried home to the Prison, and there for many days kept with bread and water, so that had the proudest Anchorite, pretending to the highest abstinence, been Commoner with him, it would have tried his swiftest Devotion to keepe pace with him.

1651, Thomas Fuller, Abel Redevivus; republished as chapter 1, in The Life, Times and Writings of Thomas Fuller, D.D.‎, volume 2, London: S. Sonnenschein, Le Bas & Lowrey, 1886, page 20

O behold this ring / Whose high respect and rich validity / Did lack a parallel; yet for all that / He gave it to a commoner o'th' camp, / If I be one.

c. 1604–1605, William Shakespeare, All's Well That Ends Well, act 5, scene 3, lines 191–195