From the second edition (1989):
bonfire, n.
(ˈbɒnfaɪə(r)) Forms: Sc. 5– bane-, 6 bain-, 5–8 bone-, 6– bonfire; also 6 bonne, boane-, boun-, bond-, 7 boon(e, 8 burnfire; north. and Sc. 5–9 bane-, 6 bainfire. [f. bone n. 1 + fire = fire of bones. The etymological spelling bone-fire, Sc. bane-fire, was common down to 1760, though bonfire was also in use from the 16th c., and became more common as the original sense was forgotten. Johnson in 1755 decided for bonfire, ‘from bon good, (Fr.) and fire’. But the shortening of the vowel was natural, from its position; cf. knowledge, Monday, collier, etc. In Scotland with the form bane-fire, the memory of the original sense was retained longer; for the annual midsummer ‘banefire’ or ‘bonfire’ in the burgh of Hawick, old bones were regularly collected and stored up, down to c. 1800.]

1. A fire of bones; a great fire in which bones were burnt in the open air. Obs.
(The 17th c. quotations are chiefly allusive, implying a knowledge that bon(e)fires ought to burn bones.)

1483 Cath. Angl. 20/1 A banefyre, ignis ossium. 1493 Festyvall (W. de W. 1515) 105 In worshyppe of saynte Johan the people waked at home, & made iij maner of fyres. One was clene bones and noo woode, and that is called a bone fyre. a1552 in Leland Brit. Coll. I. p. lxxvi, In some parts of Lincolnshire‥on some peculiar nights, they make great fires in the public streets of their Towns with bones of oxon, sheep, &c. which are heaped together before. I am apt to believe‥that from hence came the original of Bonefires. 1586 Marlowe 1st. Pt. Tamburl. iii. iii, Making bonfires for my overthrow. But, ere I die, those foul idolaters Shall make me bonfires with their filthy bones. 1684 Dineley Dk. Beaufort's Progr. Wales 154 A fire of joy‥called a Bonfire‥being part wood and part bones. [1655 Fuller Ch. Hist. ix. 52 Both parties‥would in a bonefire of their generall joy, have burnt this unhappy bone of dissention cast betwixt them. 1674 W. Stanley Rom. Horseleech 82 (Skeat) Causing all the bones of Becket to be burnt‥and how his arms should escape that bonefire is very strange.]

2. A fire in which to consume corpses, a funeral pile, a pyre. (The ordinary transl. of L. pyra, rogus in 16–17th c.) Obs.

1552 Huloet, Bonefyre‥pyra. 1565 Golding Ovid's Met. vii. Or els without solemnitie were burnt in bone-fires hie. 1583 Stanyhurst Æneid iv. (Arb.) 119 Madlye she [Dido] scaleth Thee top of her banefyer. 1639 Horn & Robotham Gate Lang. Unl. xcvii. §961 The dead corps is buried: they of old made a bone-fire, and therein burnt it. 1658 Sir T. Browne Hydriot. ii. 22 Burning [was] perhaps not fully disused till Christianity fully established gave the finall extinction to these sepulchrall Bonefires.

3. A fire for immolation; a fire in which heretics, bibles, or proscribed books were burnt. Still familiarly applied to a great fire for burning up thorns, brushwood, or rubbish, though, as the purpose is not now specifically considered as constituting a bonfire, not distinguished from sense 4b.

1581 J. Bell Haddon's Answ. Osor. 483/2 You would have made boanefiers with ye blood of many good Preachers. 1611 Speed Hist. Gt. Brit. vi. ix. (1632) 79 Their holy Bibles cast into Bone-fires. 1638 Shirley Mart. Soldier iv. ii. in Bullen O. Pl. (1882) I. 228 Methinks Christians make the bravest Bonefires of any people in the Universe. 1640 Brome Sparagus Gard. i. v. 132 Making a Bon-fire in Smithfield. 1653 A. Wilson Jas. I, 47 He [James I] thanks them for the Bonefire they made of certain Papers. 1678 Butler Hud. iii. ii. 1543. 1711 Addison Spect. No. 98 ⁋3 Many of the Women threw down their Head-dresses in the Middle of his Sermon, and made a Bonfire of them. 1845 S. Austin Ranke's Hist. Ref. II. 9 Luther's writings were collected and publicly burned; but the emperor might be seen to smile ironically as he passed these bonfires.

b. (Ireland) An incendiary fire. Obs.

1633 T. Stafford Pac. Hib. ii. (1821) 231 That‥the County of Clare might be freed from bonfires. Ibid. xvii. 183 They departed, before they had made any Bonfiers in Mounster.

4. A large fire kindled in the open air for a celebration, display, or amusement: a. (orig.) on certain anniversaries, esp. on the eves of St. John and St. Peter (cf. Fr. feu de la Saint-Jean, Ger. Johannis feuer, and bale-fire). These were originally bone-fires in sense 1 (where cf. quot. 1493), and appear to have come down from heathen times.

1493 Privy Purse Exp. Hen. VII, in Brand Pop. Ant. (1870) I. 174 To the makyng of the bonefuyr on Middesomer Eve, 10s. 1570 B. Googe Pop. Kingd. iv. 54b, Then doth the ioyfull feast of John the Baptist take his turne, When bonfiers great with loftie flame, in every towne doe burne. 1575 Ord. Cooks Newcastle in Brand Pop. Ant. (1870) I. 178 The said Felloship of Cookes shall yearelie‥mainteigne and keep the Bone-fires‥that is to say, one Bone-fire on the Even of the Feast of the Nativitie of St. John Baptist‥and the other on the Even of the Feast of St. Peter the Apostle. 1581 Sc. Acts Jas. VI (1597) §104 Setteris out of Bane-fyers, singers of Carrales‥and of sik vthers superstitious and Papisticall rites. 1600 Rowlands Let. Humours Blood iv. 65 At leaping ore a Midsommer bon-fier. 1867 in Brand Pop. Ant. (1870) I. 177 Bonfires are still made on Midsummer Eve, in the northern parts of England and in Wales.

b. (In general modern use) in celebration of some event of public or local interest, or on some festive occasion, as a victory, jubilee, the birth or marriage of the heir to an estate, etc.; but also applied to any great blazing fire made for amusement, or combining amusement with the burning of rubbish, thorns, weeds, etc. (Cf. sense 3.)
(The Fifth of November bonfires combined various senses of the word.)

1530 Palsgr. 199/2 Bonne fyre, fev de behovrdis. 1556 Chron. Gr. Friars (1852) 32 Commandement‥that there shulde be a gret bonfyer at Powlles churche dore‥for the good tydynges. 1558 Maitland Quenis Maryage, All burrows townis‥To maik bainfyres, fairseis and clerk~playis. 1582 North Gueuara's Diall Pr. 73b Great bond~fires. 1591 Raleigh Last Fight Rev. 17 Celebrate the victorie with bonefiers in euerie town. 1603 Drayton Bar. Warres iv. xxiii, With Bells and Bone-fires welcomes her ashore. 1660 Boyle New Exp. Phys. Mech. xxxvii. 309 The People‥testified their Joy by numerous Bon-fires. 1710 Addison Whig-Exam. No. 2 ⁋9 The mob has huzza'd round bonefires. 1736 Byrom Rem. (1856) II. i. 35 You have had burnfires and bells and shooting and drinking. 1772 Priestley Inst. Relig. (1782) I. 384 Our custom‥of making bonfires on the fifth of November. 1836 W. Irving Astoria (1849) 365 They built a great bonfire‥and men and women danced round it. 1848 Macaulay Hist. Eng. I. 631.

c. attrib. or comb.

1596 Shakes. 1 Hen. IV, iii. iii. 47 Thou art a perpetuall Triumph, an euerlasting Bone-fire-Light. 1690 Hist. Wars Ireland 111 Bonfire-Works‥were no sooner lighted, but the Allarm-Signal was given.