The Spanish verb 'vender' (to sell) comes from the Latin verb 'vendere', which also meant 'to sell'. The Latin 'vendere' itself is a compound word formed from two parts: 'venum' meaning 'sale' and 'dare' meaning 'to give'. So etymologically, the concept of selling was understood as 'to give for sale' in Latin, which then evolved into the Spanish word we use today.

Some common Spanish words related to 'vender' include 'venta' (sale), 'vendedor' (seller), and 'vendible' (saleable). These words all share the same Latin root and form part of the commercial vocabulary family in Spanish.

While English 'vend' and 'vendor' are related to Spanish 'vender', they are less common than their Spanish cousins. You might recognize them from 'vending machine' or 'vendor' (someone who sells). The English words were borrowed from the same Latin source 'vendere'. Another related English word is 'vendue', an archaic term for an auction or public sale.