I. bob 1 /bɒb $ bɑːb/ BrE AmE verb ( past tense and past participle bobbed , present participle bobbing )
[ Sense 1-3: Date: 1300-1400 ; Origin: Perhaps from bob 'to hit, punch' (13-19 centuries) , from the sound. ]
[ Sense 4: Date: 1900-2000 ; Origin: ⇨ ↑ bob 2 (1) ]
1 . MOVE ON WATER [intransitive] to move up and down when floating on the surface of water:
The boat bobbed gently up and down on the water.
2 . MOVE SOMEWHERE [intransitive always + adverb/preposition] to move quickly in a particular direction:
Mrs Foster bobbed about, gathering up her things.
3 . bob your head to move your head down quickly as a way of showing respect, greeting someone, or agreeing with them:
He spoke to the girl, who bobbed her head.
4 . CUT HAIR [transitive] to cut someone’s, especially a woman’s, hair in a bob:
her neatly bobbed hair
II. bob 2 BrE AmE noun [countable]
[ Sense 1: Date: 1900-2000 ; Origin: bob 'bunch (of hair)' (14-20 centuries) , perhaps from Scottish Gaelic baban ]
[ Sense 2: Date: 1800-1900 ; Origin: ⇨ ↑ bob 1 ]
[ Sense 3: Date: 1700-1800 ; Origin: Perhaps from Bob , an informal name for someone called Robert ]
1 . a way of cutting hair so that it hangs to the level of your chin and is the same length all the way round your head
2 . a quick up and down movement of your head or body, to show respect, agreement, greeting etc:
The maid gave a little bob and left the room.
3 . ( plural bob ) informal a ↑ shilling (=coin used in the past in Britain) :
At last I’m making a few bob (=a reasonable amount of money) .
⇨ bits and bobs at ↑ bit 2 (7)