Yard lumber refers to the lumber that is used for general building purposes. Yard lumber is graded by the size and length of the wood.
A yazoo tributary or stream is a small tributary that is prevented by levees or embankments from joining the main channel.
Yellowing refers to the yellowish cast on any clear, white or light-colored material due to aging, heat or cleaning.
Yield strength refers to less than the allowable stress to strain wherein the ratio of stress to strain for a particular structural component has dropped below maximum attainable stress.