The word 'tiptop' is a reduplicative compound, formed by combining two near-synonyms for the highest point. 'Tip' entered English with a sense of a small end or point, while 'top' is a native English word for the summit or uppermost part. Their pairing in the 18th century created an emphatic expression for the absolute peak, leveraging the reinforcing logic of repetition seen in other compounds like 'shipshape'. The literal sense of the "top of the top" or the "point of the summit" evolved naturally into its modern figurative meanings denoting the highest quality or degree of excellence.

Structure: tip (point) + top (summit) - tip: From Middle English 'tip', of uncertain origin, possibly from Old Norse. Functional role: Noun base meaning a point or extremity. - top: From Old English 'top' (summit, crest). Functional role: Noun base meaning the highest part.