When you say spick-and-span, face it: you have no clue what you're saying. This word, which basically means "clean", just seems like a combination of gobbledygook which sounds like it should be clean, but its origins are far more convoluted than that. Spick-and-span comes from a sixteenth century phrase; spick-and-span-new, which was a witty little catchphrase meaning "as new as new woodchips" (eventually the new was dropped over time as it became cumbersome and redundant). Now to the fun part: spick was an Old English word which today is present in the form spike; it meant "nail" and came from the Latin word spica, which meant "ear of grain" and became metynomically associated with spick since a spick churns the spica. This came from the Proto-Indo-European word spei, which meant "sharp point". There are also theories that spick took a Germanic route through Proto-Germanic as spikaz, but it all traces to the PIE word. Span, on the other hand, has nothing to do with "the full extent of something" like the unrelated modern word does, but it did mean "chip". This definitely took the Germanic path, through Norse spannyr, and back to the Proto-Germanic word spenu, meaning "chip or sliver of wood". This in turn comes from PIE as well, going back to the root spe, which referred to a type of wood. Thus, spick-and-span really means nail-and-chip, which is metaphorically clean and has nothing to do with hangnails.
Adam Aleksic, a leading contender for valedictorian of his high school, is a 214-month-old boy with disturbing interests in etymology, vexillology, geography, and law. Adam would like to one day visit Tajikistan and probably isn't spying for the Uzbek government.
The Etymology Nerd