firstly

Coined between 1525 and 1535 from first +‎ -ly.[1]

• IPA^(key): /ˈfɜɹstli/

firstly (not comparable)

1. (formal) In the first place; before anything else; first.
   • 1992, Rudolf M[athias] Schuster, The Hepaticae and Anthocerotae of North America: East of the Hundredth Meridian, volume V, New York, N.Y.: Columbia University Press, →ISBN, page vii:

     Firstly, I continue to base most species treatments on personally collected material, rather than on herbarium plants. […] Secondly, I continue to base my concepts on intensive study of a limited suite of collections, rather than superficial study of every packet that comes to hand.

• Whether it is proper to use "firstly", rather than "first", has often been disputed.
  • Beginning in the early 19th century, some have argued against the use of "firstly", advocating the sequence: "First", "secondly", "thirdly", ....
  • The usage of "firstly" is also deprecated by some modern style guides.[2] The Chicago Manual of Style further recommends that all such -ly forms be avoided, and that list items begin only with "first", "second", and so forth.[3]
  • Other authorities disagree.
    • The American Heritage Dictionary comments:

      It is well established that either first or firstly can be used to begin an enumeration: Our objectives are, first (or firstly), to recover from last year's slump.[4]

    • The Oxford English Dictionary notes the dispute but does not pass judgment: "many writers prefer first, even though closely followed by secondly, thirdly, etc."[5]
  • "Firstly" may appear more formal than "first" and is often recommended for the formal enumeration of arguments.[6]

• 1stly, first, first of all, first up; see also Thesaurus:firstly

• at first
• in the first place