The term MADRES can be solved by the 6-letter word SIERRA. MADRES is a Spanish word meaning 'mothers' and is often used to refer to the mothers of those who have been killed or disappeared in Latin America due to political violence. The word SIERRA is derived from the Spanish word for mountain range, which is often used to symbolize strength and resilience. Thus, the term MADRES can be interpreted as a tribute to the strength and resilience of the mothers of those affected by political violence in Latin America.