What are the parts of a padlock?

Answer 1

There are many different types of padlocks, so exact terminology will vary. Here are some of the more common terms though:

The shackle - the U-shaped piece that locks down

"Hardened" - this refers to tempering of the shackle to make it more resistant to bolt cutters

Plug - The part that the key goes into

Keyway - The milled out portion of the Plug

Tumblers - The small pieces that "read" the key

Body - the main part of the padlock

Retaining screw - on some padlocks this is in the hole the shackle normally sets it, this holds the lock cylinder in.

Source:

http://www.locksafesystems.com/