The Spanish word 'estilo' (meaning 'style') comes from the Latin word 'stilus', which originally referred to a pointed instrument used for writing on wax tablets in ancient times. This writing tool, or stylus, was so fundamental to the way people wrote that its name eventually came to represent the manner or characteristic way of writing itself. Over time, this meaning broadened beyond just writing to encompass any distinctive manner of doing something, leading to our modern concept of 'style'.

The phonetic evolution from Latin 'stilus' to Spanish 'estilo' shows a common Spanish development where words beginning with 's' + consonant received a helping vowel 'e-' at the start (called a prosthetic vowel). This pattern can be seen in many Spanish words derived from Latin, like 'escuela' from 'schola' or 'espacio' from 'spatium'.

Some related Spanish words include 'estilográfica' (fountain pen), which maintains a connection to the original meaning of writing instrument, and 'estilista' (stylist), which relates to the modern meaning of style and fashion.

English speakers will recognize this connection in words like 'style' and 'stylus', both of which share the same Latin ancestor. The word 'stylistic' and even 'stiletto' (originally a slender dagger, named for its resemblance to a writing stylus) are also related. This shows how a simple writing tool gave rise to a whole family of words related to both writing implements and manner or fashion.