/sɒlv/
[verb] To find the answer to a problem or to explain something that was difficult or unclear. It can also mean to find a way to deal with a difficult situation successfully.
'Solve' originally meant to loosen or untie — ancient Romans thought of problems as knots waiting to be undone.
The word 'solve' traces its roots to the Latin verb *solvere*, meaning 'to loosen, untie, release, or free.' The Romans used this word in very physical, tangible ways — to describe untying a rope, releasing a prisoner, or dissolving a substance in liquid. The idea at its heart was one of setting something free from a tight or tangled state.
This Latin root *solvere* was itself built from two older pieces: the prefix *se-* (meaning 'apart' or 'away') combined with *luere* (meaning 'to loosen' or 'to release'), a verb distantly related to the Greek *lyein*, which also meant 'to loosen.' This ancient Indo-European idea of loosening or untying runs through many languages and centuries, reflecting a deep human instinct to describe the resolution of difficulty as a kind of unbinding.
From *solvere*, Latin gave English a remarkable family of words. *Solvere* became *solutio* in Latin, which passed into Old French as *solution*, and from there into Middle English as 'solution' in the 14th century — originally referring to the dissolving of a substance in liquid, before it took on the meaning of an answer to a problem. The past participle of *solvere* was *solutus*, meaning 'loosened' or 'freed,' which is where we get 'solute' (a dissolved substance) and 'absolute' (from Latin *absolutus*, meaning completely freed from restriction).
'Solve' itself entered English in the 15th century, borrowed directly from Latin *solvere*, and at first it was used mainly in scientific and alchemical contexts to mean dissolving a solid substance in a liquid. The idea of 'solving a problem' — of mentally untying a difficulty — developed gradually over the following century, as thinkers in mathematics and philosophy began using the word to describe working out puzzles and equations. By the 16th and 17th centuries, this intellectual meaning had become firmly established.
The financial world also borrowed heavily from *solvere*. The Latin word *solvere* was used to mean 'to pay a debt,' since paying off a debt was understood as releasing yourself from an obligation — another form of untying. This is where the English words 'solvent' (financially stable, able to pay debts) and 'insolvent' (unable to pay) come from. When a company goes bankrupt today, we still feel the ghost of that ancient Roman image: the knot of debt that could not be undone.
What makes 'solve' so quietly remarkable is how it reminds us that the way we talk about abstract thinking is rooted in physical experience. To solve a problem is not, in the modern imagination, a very bodily act — but the word insists otherwise. Every time a mathematician cracks an equation or a detective unravels a mystery, they are, in the oldest layer of the language, simply untying a knot.