The Spanish word 'amistad' (meaning 'friendship') traces back to the Latin verb 'amare' meaning 'to love'. From this verb, Latin formed the word 'amicus' (meaning 'friend') by adding the relational suffix '-icus'. This Latin word then evolved into the Vulgar Latin term '*amicitas' meaning 'friendship', which eventually developed into the modern Spanish 'amistad'.

The evolution from Latin 'amicus' to Spanish 'amistad' shows how a word meaning 'friend' was transformed into an abstract noun representing the concept of friendship, maintaining the core meaning of affection and companionship throughout its history.

The most common related Spanish word is 'amigo' meaning 'friend', which comes directly from the Latin 'amicus'. This is likely one of the first words Spanish learners encounter, and it helps to remember that 'amistad' is simply the abstract quality or state of being an 'amigo'.

While English 'friendship' comes from Germanic roots, English has borrowed several words from the same Latin source as 'amistad'. These include 'amicable' (friendly), 'amiable' (friendly, pleasant), and even 'amateur' (originally meaning 'lover of' something). All these words share the Latin root 'amare' meaning 'to love', though they've developed different shades of meaning over time.