The Spanish verb 'convertir' (meaning 'to convert' or 'to transform') comes from the Latin word 'convertere', which had the same meaning of 'to turn completely' or 'to transform'. The Latin 'convertere' was formed by combining two elements: the prefix 'con-' meaning 'together' or 'with', and the verb 'vertere' meaning 'to turn'. So literally, the word was built to mean 'to turn together' or 'to turn completely', which evolved into the modern sense of conversion or transformation.

Several common Spanish words share the same Latin root 'vertere' (to turn). These include 'verter' (to pour, spill), 'verso' (verse, as in poetry - originally referring to the 'turning' of the line), and 'invertir' (to invert or invest). The prefix 'con-' is also very productive in Spanish, appearing in many words like 'construir' (to construct) and 'contener' (to contain).

English speakers can easily remember 'convertir' by connecting it to the English word 'convert', which comes from the same Latin source 'convertere'. Other English words from the same Latin root 'vertere' include 'verse', 'version', 'reverse', 'divert', and 'invert'. All these words maintain some connection to the original idea of 'turning' - whether literally or figuratively.