petty larceny vs theft

petty larceny and theft both are nouns.

Word	Noun	Adjective	Verb	Adverb
petty larceny	Yes	No	No	No
theft	Yes	No	No	No

As nouns, theft is a hypernym of petty larceny; that is, theft is a word with a broader meaning than petty larceny:

petty larceny: larceny of property having a value less than some amount (the amount varies by locale)
theft: the act of taking something from someone unlawfully

Other hypernyms of petty larceny include larceny, stealing, thievery, thieving.

petty larceny (noun)	theft (noun)
larceny of property having a value less than some amount (the amount varies by locale)	the act of taking something from someone unlawfully