You probably recognize the word spat from the phrase "lover's spat," which describes a minor squabble between a couple. The spat is usually over something as silly as which partner has to do the laundry, and the relationship usually recovers quickly, with no long-term harm done.
For the purposes of this definition, the noun spat refers to a minor argument or mild bickering. That is the definition by which spat is probably best known, but the word has other meanings. Depending on how you use spat, it can be the past participle of spit, the short piece of leather men wore over their shoes in the old days, or an oyster that hasn't quite reached its prime.