Firstly

Part of speech: adverb

Pronunciation: /ˈfɜɹstli/

Definitions

1. In the first place; as the initial point in a series of statements or arguments
2. As an introductory term, it is utilized to present the foremost argument in a series of considerations or discussions
3. Used to introduce the first item or reason in a sequence of points

Etymology: "Firstly" is a plain piece of English word-building: the adjective "first" with the adverb-forming suffix "-ly" attached. The suffix comes from Old English "-lic," a form related to "like," and its job was to turn adjectives into adverbs, so "firstly" is simply "in a first way." The word was coined before 1475, and its earliest form was "fyrst-lyk," a Middle English spelling that kept the older "-lyk" ending, which was later worn down to "-ly." The adverb was therefore already in use in an early stage of English, and it has kept its sense of ordering points in a list ever since.

Synonyms: initially, primarily, to begin with, at first, in the first place