The Spanish word 'nuestro' (meaning 'our') comes from Latin 'nostrum', which was the accusative form of 'noster' (meaning 'our'). The Latin 'noster' itself was derived from 'nos' meaning 'we'. The development from Latin 'nostrum' to Spanish 'nuestro' shows a typical sound change where the Latin 'o' became the Spanish diphthong 'ue', a common pattern in Spanish evolution from Latin words.

The Spanish pronoun 'nosotros' (meaning 'we') is related to 'nuestro' as they both derive from the same Latin root 'nos'. While 'nuestro' developed from the possessive form, 'nosotros' literally developed from 'nos otros' meaning 'we others'.

While not immediately obvious, English words like 'nostril' (originally meaning 'our hole') and 'nostrum' (meaning a questionable medicine or remedy) are distantly related. 'Nostrum' in particular is directly borrowed from Latin, where it literally meant 'our (remedy)' - it was used in medieval Latin phrases like 'nostrum remedium' (our remedy), eventually being used ironically for questionable cure-alls.