The ability of a segment of a glass sphere to magnifywhatever is placedbefore it was knownaround the year 1000, when the spherical segment was called a reading stone, essentially what today we might term a framelessmagnifying glass or plainglasspaperweight.
Meaning of -less for the defined word.
Grammaticalement, ce mot "-less" est un morphème, plus spécifiquement, un suffixe.