Overhang
Increase in printed circuit conductor width caused by plating build-up or by undercutting during etching.
Outgrowth
The increase in conductor width at one side of a conductor, caused by plating build-up, over that delineated on the production master.
Outgassing
The gaseous emission from a laminate printed board or component when the board or the printed board assembly is exposed to heat or reduced air pressure or both.
OSP
Organic Solderable Preservative.
Organic Activated (OA)
A water-soluble flux using organic acids as activators.
Open
An area of a bare PCB which, due to over-etching or fabrication problems, separates two electrically connected points.
One-sided Board
See Single-sided Board.
Omegameter
A test instrument measuring ionic residues on PCBs via the drop of resistivity over a specific time.