A sailboat with its bow pointed directly into the wind, preventing the sails from filling properly and stopping the boat. It can be very difficult to get a boat that is in irons back under sail. also known as "In Stays".
The difference between the input quantity applied to a measuring instrument and the output quantity indicated by the instrument. The inaccuracy of an instrument is equal to the sum of its instrument error and its uncertainty.
Particles of foreign material in a metallic matrix. The particles are usually compounds (such as oxides, sulfides, or silicates), but may be of any substance that is foreign to (and essentially insoluble in) the matrix.