The periodic table and other uses for the letters Pb.

Entry: 

Pb is the symbol for lead in the periodic table.

Some other things that use Pb as a symbol:
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Play back
Personal best
Peanut butter
Paper back
Polar bear
Private banking
Page break
Primary beam
Punk buster
Project builder
Piggy back
Performance benchmark
Personal banking
Pooh bear
Printer board
Pure bred
Pass back
Power booster
Playboy bunny
Productive burp
Practical business
Photon blast
Previous balance
Player’s book
Parabolic barrier
Physio ball
Prayer beast
Paddington bear
Prominent blogger
Performance barn
Pineapple bacon
Pushy broads
Poor backup
Project Bucharest
Parliamentary broadcast
Plenty bigoted
Panic button
Patrol boat
(above from www.abbreviations.com)

Some other things for which Pb could be used as a symbol, if you wanted to:
Pitta bread
Pringle box
Pumping bar
Permeating brand
Partly broken
Perfunctory bruise
Pork bun
Purple blaze
Pendulum beat
Pants boy
Pin bin
Pepper binge
Peat bog
Play boy
Pity bonk
Pontoon bridge
Pull bit
Possible barfight
Police baton
Proportional beating
Personal binliner
Production blurb
Priceless bill
Project buccaneer
Powerful blowjob
Penis borehole (otherwise known as a gentleman’s dock, or fluid receptacle)
Perspective boyfriend
Porno book
Parking bay
Public billions
Pitcher based
Purchased badly
Presidential budget
Patriot baby
Phonebox bomb
Pushup bra
Picturesque burnout
Plausibly belligerent
Poor bombshell
Particular
Poking buffer
Portentous briar
Plate boat
Plane bump