As far as a textbook definition goes, I probablly could not give it to you, but the use of TYP is pretty simple. If something is Typical, say so...
1. in lieu of counting and giving the discrete number of instances.
for example if you have a sheet metal part where all the break radi is .5 in, you would leader one radius and annotate ".50 TYP".
or
2. If you have a detail that occurs in 6 places on the drawing, you can add to the detail title "TYP 6 PL" meaning that all six places are the same.
Bacically you are saying all the things that look like "THIS" mean "THIS"
Wes C.
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When they broke open molecules, they found they were only stuffed with atoms. But when they broke open atoms, they found them stuffed with explosions...