MML explained

MML can stand for:

Academia

Master of Modern Languages, an undergraduate degree offered by the University of Manchester, which includes the study of two modern languages to Master's level
Medieval and Modern Languages, an undergraduate degree offered by the Faculty of Medieval and Modern Languages, University of Oxford (FMML)
Modern and Medieval Languages, an undergraduate degree offered by (and the corresponding faculty at) the University of Cambridge

Medical Markup Language, an application of Extensible Markup Language (XML).
MML (language), man-machine language, a computer language.
Modeling Maturity Level, a scale to indicate to which degree an architecture uses models (used in software development).
Music Macro Language, a music notation format used in producing music for personal computers and video game systems.
Music Markup Language, an application of Extensible Markup Language (XML).
An abbreviation for the voice over IP application Mumble, primarily designed for use by Scottermac (mml).

Maskew Miller Longman, a South African publishing company part-owned by the UK's Pearson Plc
Michigan Municipal League, a non-profit organization representing Michigan cities, villages and urban townships
MML Capital Partners an international investment company
Material Measurement Laboratory, a NIST laboratory since 2010

Metropolitan Municipality of Lima (Spanish; Castilian: Municipalidad Metropolitana de Lima), the government institution in charge of the metropolitan area of Lima, Peru

2050 in Roman numerals
Minimum Message Length, a form of unbiased statistical modeling based on information theory
MyMathLab, an online education platform, developed by Pearson Education, for teaching and learning mathematics

The IATA airport code for Southwest Minnesota Regional Airport
The Midland Main Line, a main line railway in the United Kingdom
Midland Mainline (train operating company), a former train operating company that operated the Midland Main Line franchise.
Midland Line (disambiguation), for other uses