Difference between squabble and bicker

Squabble tends to imply a fight among children, or among people acting like children. Bicker, on the other hand, evokes the fights of an unhappy couple.

I agree with @buildsucceeded answer however I would add that squabble is usually something very temporary and can be finished quickly. Maybe that is why it is used with kids. Kids don't usually hold grudges. They would squabble over who gets to go first.

Bicker is used for contemptuous, bitchy fighting that has more of a history. And even though two (or more) people may quit bickering, they can go right back to bickering easily. To me it implies that whatever they are bickering about is only a surface issue and that the people bickering have more conflicts.

And let's go back to the "kids" example. Normally kids would squabble not bicker. However brothers and sisters can definitely bicker.

For me the difference is in common usage. As a native American English speaker, I most often hear squabble used in its noun form. For example, "They had a little squabble." I don't know that I have ever heard another native speaker use squabble as a verb. Bicker on the other hand does not have a noun form that I am aware of.

Another difference that arises from experiences of usage is bickering can be a one sided affair. That is to say, I may not be up for an argument, but my wife may still be bickering at me about something. Squabble on the other hand is typically used to describe a spat between two individuals.

Please note that my answer is not meant to imply that these experiences represent "rules of usage" rather, they are simply what I have experienced as a native American English speaker.

Here is how various dictionaries—starting with the 1756 edition of Samuel Johnson's Dictionary and ending with Merriam-Webster's Eleventh Collegiate Dictionary (2003)—have defined bicker and squabble over the past 250 years or so.

Johnson's Dictionary (1756):

To BICKER 1. To skirmish; to fight off and on. 2. To quiver; to play backward and forward.

To SQUABBLE To quarrel; to debate peevishly; to wrangle.

Webster's Compendious Dictionary (1806):

BICKER to dispute about trifles, quiver

SQUABBLE to wrangle, debate peevishly, brawl

Webster's American Dictionary (1828):

BICKER 1. To skirmish; to fight off and on; that is, to make repeated attacks. [But in this sense I believe rarely used.] 2. To quarrel; to contend in words; to scold; to contend in petulant altercation. [This is the usual signification.] 3. To move quickly; to quiver; to be tremulous like flame or water; as the bickering flame; the bickering stream.

SQUABBLE 1. To contend for superiority; to scuffle; to struggle; as, two persons squabble in sport. 2. To contend; to wrangle; to quarrel. 3. To debate peevishly; to dispute. [Squabble is not an elegant word in any of its uses. In some of them it is low.]

Worcester's Comprehensive Dictionary (1845):

BICKER to skirmish; to quiver

SQUABBLE to quarrel; to fight

Webster's New University Pronouncing Dictionary (1864):

BICKER To dispute about trifles; to have a tremulous motion.

SQUABBLE To debate peevishly; to wrangle; to contend; to brawl; to quarrel.

Webster's Academic Dictionary (1874):

BICKER 1. To contend in words or petulant altercation. 2. To be tremulous, like flame.

SQUABBLE 1. To contend for superiority. 2. To debate peevishly

Webster's Academic Dictionary (1895):

BICKER 1. To wrangle. 2. To quiver; to be tremulous, like a flame.

SQUABBLE 1. To contend for superiority in an unseemly manner; to wrangle; to quarrel. 2. To debate peevishly. v.t. To disarrange (type in printing).

Webster's [First] Collegiate Dictionary (1908):

BICKER 1. To fight. [Obs.] 2. To altercate petulantly; to wrangle. 3. To move with a babbling noise; to quiver.

SQUABBLE 1. To contend for superiority in an unseemly manner; to wrangle; to quarrel. 2. To debate peevishly. v.t. To disarrange so that readjustment is necessary;—said of type that has been set up.

Webster's [Fifth] Collegiate Dictionary (1944):

BICKER 1. To contend petulantly; wrangle. 2. To move quickly and unsteadily; quiver; flicker.

SQUABBLE To quarrel noisily; to wrangle. v.t. To disarrange so that the letters or lines need readjustment;—said of type that has been set up.

Webster's [Seventh] Collegiate Dictionary (1965):

BICKER 1 to contend in petulant or petty altercation 2a to move quickly and unsteadily with a rapidly repeated noise b quiver, flicker

SQUABBLE to quarrel noisily and to no purpose: wrangle vt: to disarrange (set type) so that the letters or lines need readjustment

[First] American Heritage Dictionary of the English Language (1971):

BICKER 1. To engage in a petty quarrel; to squabble. 2. Poetic, To flicker; glisten; quiver.

SQUABBLE To engage in a minor quarrel; bicker.

[Usage note:] Wrangle refers to loud contentious argument, and squabble to minor argument over a petty or trivial matter. ... Bicker suggests sharp, recurrent exchange of remarks on a mean or petty level.

Longman Dictionary of Contemporary English (1987):

BICKER to quarrel, esp. about unimportant matters: The two children were always bickering (with each other) (over/about their toys).

SQUABBLE to take part in a continuing quarrel, esp. over something unimportant: What are you two children squabbling about now?

Encarta World English Dictionary (1999):

BICKER to argue in a bad-tempered way about something unimportant

SQUABBLE to have a petty argument over a trivial matter

[Fourth] American Heritage Dictionary of the English Language (2000):

BICKER 1. To engage in a petty, bad-tempered quarrel; squabble. 2. To flicker; quiver.

SQUABBLE To engage in a disagreeable argument, usually over a trivial matter; wrangle.

[Usage note:] Squabble suggests petty or trivial argument. Bicker connotes sharp, persistent, bad-tempered exchange.

[Tenth] Concise Oxford English Dictionary (2001):

BICKER 1 argue about petty and trivial matters 2 poetic/literary (of water) flow with a gentle repetitive noise

SQUABBLE engage in a squabble [[defined as "a trivial noisy quarrel"]]

Merriam-Webster's [Eleventh] Collegiate Dictionary (2003):

BICKER 1: to engage in a petulant or petty quarrel 2a: to move with a rapidly repeated noise b: quiver, flicker

SQUABBLE to quarrel noisily and usu. over petty matters

In these definitions, it's hard to find support for the notion that bickering is for adults and squabbling is for children. But the similarity in meaning of the two terms across many decades is striking—especially with regard to the elements of pettiness and petulance. Though bicker may have a slightly stronger connotation of persistent or habitual quarreling, the 1987 Longmans definition of squabble stresses the "continuing quarrel" that it may imply.

"Bicker", to my mind, suggests an ill-tempered verbal exchange, while "squabble" is a more general term for a minor, and perhaps childish, feud.

"Bicker", to my mind, suggests an ill-tempered verbal exchange, while "squabble", to me is a more general term for a feuding childishly.