LLB is derived from a Latin word "Legum Baccalauerues" in which "Legum" means law. Traditionally, in India either BL or LLB was awarded. Both of them were treated as equal, that is "Bachelors of Law". However, now the Bar Council of India awards BA LLB for 5-year undergraduate law course and LLB for 3-year graduate law course with the abbreviation of the previous course completed by the students, for example if completed B.com, then B.com LLB, B.Sc, then B.Sc LLB etc. Both of these 3-year and 5-year law courses are approved by the Bar Council of India as a primary requirement to practice law in India.
Again similarly both ML and LLM are the same. Both stand for "Masters of Law". This word is derived from a Latin term "Legum Magister".