Bútan

According to the Old English Dictionary:

búton, bútun;

bútan

conj. [be, útan out]. I. with the subj. Unless, save that; nisi :-- Bútan ðú [eorþan spéde] gedǽlde Dryhtne sylfum unless thou hadst bestowed [the riches of the earth] for the Lord himself, Exon. 99a; Th. 371, 19; Seel. 78. Búton ðæt hit sý útaworpen nisi ut mittatur foras, Mt. Bos. 5, 13. Bútan ǽr wyrce éce Dryhten ende worlde save ere the eternal Lord shall work an end of the world, Exon. 98a; Th. 367, 24; Seel. 12. II. with the ind. Save or except that; nisi :-- Egorhere eall acwealde búton ðæt earce bord heóld heofona freá the water-host destroyed all save that the Lord of heaven held the ark board, Cd. 70; Th. 84, 26; Gen. 1403. III. without a dependent verb, Except, save, besides, but; nisi :-- Ond eallum dagum bútan sunnan dagum diebus cunctis excepta dominica, Bd. 3, 23; S. 554, 32. Ic ne gehýrde bútan hlimman sǽI heard nought save the sea roaring, Exon. 81b; Th. 307, 4; Seef. 18. Sume men sǽdon ðæt ðǽr nǽran bútan twegen dǽlas some men said that there were but two parts. Ors. 1, 1; Bos. 15, 6. butan