Namely means that is to say, and introduces the specific ones you mean. Namely these three, namely the cost, namely that.
It narrows a general statement to particulars: two problems remain, namely cost and time. It is followed by a complete list, which is what separates it from such as and including, both of which introduce examples rather than the whole. Note viz., the abbreviation of the Latin videlicet, which does the same job in formal writing and is read aloud as namely.
1adverbnamelyThat is to say, introducing the specific ones you mean.
“Only one student failed the exam, namely the one who never came to class.”
namely is a specifying word.
Middle English nameliche is name plus -ly, and every Germanic language has the same compound — Dutch namelijk, German nämlich, Swedish nämligen — each formed independently.
Middle English
namely
English, today
namely
From Middle English namely, nameliche, namelike, equivalent to name + -ly. Cognate with stq nämmelk, West Frisian nammentlik, Dutch namelijk, German Low German nämlich, German nämlich, Danish nemlig, Swedish nämligen, Icelandic nefnilega.
Etymology from Wiktionary, CC BY-SA