Etymonline is a site by Douglas Harper, a scholar who tracks a lot of his scholarship on Etymonline (basically, he's "not an etymologist"; but he's read many of 'the places words come-from' (a.k.a. books, but also articles, encyclopedias, movies, plays, TV-shows, radio, songs, etc.) and he shares what he's learned (when he's not teaching or doing something else).
The name Etymonline is a portmanteau of "Etymology (or maybe Etymological Dictionary or maybe Etymon)" & "Online."
The word Online (meaning "Directly Connected to a Peripheral Device") is built of the words "On" & "Line."
The word "On" (related to OnTo AddOn CarryOn ClipOn GetOn GoOn HandsOn HangOn HardOn HeadOn Hereon IronOn Logon OffAndOn On- Onboard Oncoming Ongoing Onlooker Onrush Onset OnSite Onslaught Onward PutOn SideOn Thereon TurnOn Upon WalkOn Whereon) comes from a wordroot that means "In, Into, Upon, Down-from."
Line (related to Lines Lined Lining Liner Liners BeeLine Baseline Borderline ClothesLine Curvilinear Linear Delineate Inline Interline Lineage Lineal Linear Lineo- MainLine Outline Pipeline Rectilinear Streamline Underline Underlined Underlining Reline Relined Relining)
... comes from a wordroot that means "Linen Cord" (a word which also means "Boundary-Mark, Limit, Goal, Bloodline (line of Descent)").






