These days most of the English speaking world does not use the term larceny. The UK, for example, uses the legal term 'theft' to cover what was once considered larceny. America, as always, is the black sheep, and we still have the crime of larceny. We have made one change in terminology; the masses have determined that the spelling should be changed from the original 'petit larceny' to the cunningly drab 'petty larceny'. You can still find 'petit larceny' used in legal circles, but it is rarely used by the press or the common folk.
Larceny is defined as the picking up ('caption') and taking away ('asportation') of property that does not belong to you. Larceny comes in two sorts, petty larceny and grand larceny. Exactly what counts as petty versus grand larceny is determined by the value of the stolen goods; in America the determination between petty and grand larceny is set by each individual state. It is common to set petty larcenies at thefts of goods valued at less than $250, and grand larceny as anything above that. Generally a petty larceny will be considered a misdemeanor and a grand larceny a felony, although other factors, such as the use of a weapon, are also taken into account.
The terminology of larcenies was set forth in the Statute of Westminster, and English statute passed in 1275. Both grand and petit larcenies were felonies, but the punishment for grand larceny was a death sentence, while a petit larceny warranted only a whipping. In those days the relevant value of stolen property was whether it was above twelve pence, which was approximately the value of two bushels of wheat or one sheep. Why twelve pence was chosen is unknown.
And in case you were planning something, be warned, you can totally go to jail for petty larceny.