mil
Mil (noun) means a unit for measuring angles, equal to one six-thousand-four-hundredth of a full circle; at a distance of 1000 metres, one mil covers roughly one metre, though some countries instead use one six-thousandth or one six-thousand-three-hundredth of a circle.
Fill the gap
Can you complete this real example?
The plastic sheeting we bought is six _____ thick.
Etymology
Mil goes back ultimately to Latin millesimum. As a clipping, it comes by way of clipped words such as millilitre, millimetre and milliradian; as a metric unit, it arises through clipping of translingual milli- ("SI prefix").