Piston vs X - What's the difference?
piston | x |
A solid disk or cylinder that fits inside a hollow cylinder, and moves under pressure (as in an engine) or displaces fluid (as in a pump)
(music) A valve device in some brass instruments for changing the pitch
The twenty-fourth letter of the .
Image:Latin X.png, Capital and lowercase versions of X , in normal and italic type
Image:Fraktur letter X.png, Uppercase and lowercase X in Fraktur
Roman numerals
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