The Spanish word 'pequeño' (meaning 'small') comes from the Vulgar Latin word 'piccinnus', which itself evolved from Late Latin 'pitinnus'. Both Latin terms were nursery words meaning 'small' - essentially baby talk or child-like language used to describe little things. This is similar to how English speakers might use words like 'teeny' or 'itty-bitty' when speaking to children. The word evolved from 'pitinnus' to 'piccinnus' and finally to 'pequeño', maintaining its core meaning of 'small' throughout its history.

Some related Spanish words include the diminutive form 'pequeñito' (very small/tiny), and 'pequeñez' (smallness). The adjective 'pequeño' is also commonly used in phrases like 'un pequeño problema' (a small problem) or 'desde pequeño' (from an early age/since childhood).

While there aren't direct English cognates from the same Latin root, English speakers might find it helpful to associate 'pequeño' with words like 'petite' (from French, meaning small or little) or 'piccolo' (from Italian, meaning small) which, while not directly related, share a similar sound pattern and meaning related to smallness.