the.com/sawdust

means The fine powdery wood particles shed when something is sawed, cut, or sanded.

from A straightforward compound: 'saw,' the cutting tool (from Old English 'sagu,' related to the verb 'to see' only in the sense of a shared ancient root meaning 'to cut'), plus 'dust,' the Old English 'dust' for fine particles. The word just names what it is — the dust a saw leaves behind — first showing up in English in the medieval period as woodworking and milling grew common enough to need a word for their leftovers.