adverb (r)

• for the most part(adv.all)

  Example:
  He is mainly interested in butterflies.
  

  Synonym:
  chiefly, in the main, primarily, principally
  

  source: wordnet30
• Very strongly; mightily; to a great degree.(adverb)

  source: webster1913
• Principally; chiefly.(adverb)

  source: webster1913