If you mean what unit, then any distance unit, such as inches, feet, meters, yards, etc. For tools, you can use a ruler, tape measure, micrometer, caliper, yardstick, meter stick, surveyors chain, etc. to measure width, depending on what you are measuring.
There are no standard measures.
Width measures how wide, or how far across something may be. Depth, measures how deep or how far down something goes.
Ruler
When you go to shoe store, they have this feet measurement. It measures both your shoe length and width.
My small paperclip measures 1/4" total width.
They are measures of distance in 3-Dimensional space. The measures are normally in three orthogonal directions.
a ruler or a tape measure
It means it measures 87 units across.
Try multiplying the measures.
The dimensions of the canvas that measures 650x47 cm are 650 cm in length and 47 cm in width.
It is 1/2 of length x width
No, depth and width are not the same; they refer to different dimensions. Width measures the extent of an object from side to side, while depth measures how deep an object is, typically from front to back. These dimensions are used to describe the size and shape of objects in three-dimensional space.