noun

• (Scotland) strength, vigor, energy
  "Ye'll be sae kind as let me see How this same bird o' yours can flee. T'oblige ye, friend, I winna stand — Syne loos'd the falcon frae his hand. Unhooded, up she sprang wi' birr, While baith stood staring after her."
• (Scotland) The force of movement; rush, impetus, momentum, driving force
  "A chaise in full birr came upon her and knocked her down."
• (Scotland) A whirring noise
  "O' the sounds o' love and joy, There's nane sae pleasant as the birr o' Scotland's spinnin' wheel."
• (Scotland) A strong trilling.
  "Nae mair he will wi' rattlin' birr, Sing to his soul-inspirin' girr, The dormant Gothamites to stir, His powers to heed;"

verb

• (Scotland) To make a whirring noise; make a noise like that of revolving wheels, or of millstones at work.
  "if it is ordained that ye must forget him, ye will banish him from your mind the mair easily that ye ken nae mair o' him than ye do o' the bird that birrs past ye in the wood—that it has a bonny feather in its tail.""
• (Scotland) To lurch or set to spinning.
  "His cowt grew reezy, its lang tail 'Twad swash, and lugs wad birr up, At length it cuist him, and did trail Him hame, by fit i'e stirrup,"