Alférez is a junior officer rank in the militaries of Spain, Argentina, Chile and Uruguay. The Portuguese variant alferes is used in Portugal, Mozambique, São Tomé and Príncipe and East Timor and was also formerly used in Brazil. The naval rank of alférez de fragata is used in Spain, Dominican Republic and Peru.
Alférez and alferes are often translated as ensign, but are also sometimes translated as sub-lieutenant or second lieutenant. These translations are approximate. As a military rank, it corresponds usually to NATO rank code is OF-1.
The Spanish word alférez and the Portuguese word alferes were both derived from the Arabic الفارس (al-fāris), meaning "horseman", "knight" or "cavalier".
The rank of alférez / alferes was first used by Iberian armies during the reconquista in the middle ages, being associated to the officer responsible for the carrying of a unit flag. During that time alférez was the leader of the retinue of a king or high-ranking nobleman. The famous warrior El Cid was the alférez of King Alfonso VI of Castile and Alfonso Núñez was the alférez of Duke Raymond of Galicia.