The Spanish word 'amiguita' meaning 'little female friend' has its roots in the Latin word 'amare' meaning 'to love'. From 'amare' came the Latin word 'amicus' meaning 'friend', which evolved into the Spanish word 'amigo' (friend). The feminine form 'amiga' (female friend) was then combined with the Spanish diminutive suffix '-ita' to form 'amiguita', literally meaning 'little female friend'.

The diminutive suffix '-ita' is commonly used in Spanish to express smallness, endearment, or affection, making 'amiguita' a more intimate and affectionate way to refer to a female friend.

The most common related Spanish words are 'amigo' (male friend) and 'amiga' (female friend). These are among the first words Spanish students learn. Another common related word is 'amistad' meaning 'friendship'. All these words share the same Latin root 'amicus' and maintain the core meaning related to friendship and affection.

Several English words share the same Latin root 'amare' (to love). The word 'amiable' meaning 'friendly and pleasant' comes directly from this source. 'Amicable', meaning 'having a spirit of friendliness', is even closer to the Latin 'amicus'. The word 'amateur', though it might not seem obviously related, also comes from 'amare' - it originally referred to someone who does something for the love of it rather than professionally.