Definition of "MUA"

MUA

noun
plural MUAs
1. Initialism of make-up artist.
2. (computing) Initialism of mail user agent.
  Quotations
  A “mail user agent” (MUA or UA) that lets users read and compose mail[.]
  2011, Evi Nemeth et al., UNIX and Linux System Administration Handbook, Pearson Education, page 744